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Статті в журналах з теми "Groupes de type fini":
1
Champetier, Christophe. "L’espace des groupes de type fini." Topology 39, no. 4 (July 2000): 657–80. http://dx.doi.org/10.1016/s0040-9383(98)00063-9.
2
Kratzer, Charles, and Jacques Thévenaz. "Type d'homotopie des treillis et treillis des sous-groupes d'un groupe fini." Commentarii Mathematici Helvetici 60, no. 1 (December 1985): 85–106. http://dx.doi.org/10.1007/bf02567401.
3
Parreau, Anne. "Compactification d’espaces de représentations de groupes de type fini." Mathematische Zeitschrift 272, no. 1-2 (September 14, 2011): 51–86. http://dx.doi.org/10.1007/s00209-011-0921-8.
4
Jaligot, Eric. "Groupes de Rang de Morley Fini de Type Pair avec un Sous-groupe Faiblement Inclus." Journal of Algebra 240, no. 2 (June 2001): 413–44. http://dx.doi.org/10.1006/jabr.2000.8649.
5
Berteloot, F., and Gérard Cœuré. "Domaines de ${\bf C}^2$, pseudoconvexes et de type fini ayant un groupe non compact d'automorphismes." Annales de l’institut Fourier 41, no. 1 (1991): 77–86. http://dx.doi.org/10.5802/aif.1249.
6
Chaluleau, Benoı̂t, and Christophe Pittet. "Exemples de variétés riemanniennes homogènes qui ne sont pas quasi isométriques à un groupe de type fini." Comptes Rendus de l'Académie des Sciences - Series I - Mathematics 332, no. 7 (April 2001): 593–95. http://dx.doi.org/10.1016/s0764-4442(01)01879-1.
7
Goldsmith, John, and Jessie Pinkham. "Sur les phrases du type « Elle a de qui tenir »." Revue québécoise de linguistique 15, no. 2 (May 27, 2009): 273–77. http://dx.doi.org/10.7202/602570ar.
Анотація:
Résumé L’existence des phrases telles que « elle a de qui tenir », où le mot de fait partie d’une expression idiomatique, suggère qu’une position nulle peut apparaître dans certaines positions syntaxiques (par exemple, après certains verbes d’existence) si elles sont suivies par certaines structures qui se comportent comme des relatives à temps non-fini (ici, « de qui tenir »). De telles structures se rencontrent dans d’autres langues romanes. Pourtant, d’autres phrases qui ressemblent à ce premier groupe existent en français (à la différence des autres langues romanes) où le de en question n’est pas la préposition indépendente de, mais plutôt le de qui se trouve au sein du syntagme nominal uniquement en français (par exemple, « elle a de quoi boire »).
8
Lascar, Daniel. "Les Groupes ω-Stables de Rang Fini". Transactions of the American Mathematical Society 292, № 2 (грудень 1985): 451. http://dx.doi.org/10.2307/2000223.
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Lascar, Daniel. "Les groupes $\omega$-stables de rang fini." Transactions of the American Mathematical Society 292, no. 2 (February 1, 1985): 451. http://dx.doi.org/10.1090/s0002-9947-1985-0808731-2.
10
Frécon, Olivier. "Groupes géométriques de rang de Morley fini." Journal of the Institute of Mathematics of Jussieu 7, no. 4 (October 2008): 751–92. http://dx.doi.org/10.1017/s1474748008000212.
Анотація:
AbstractWe consider a new subgroup In(G) in any group G of finite Morley rank. This definably characteristic subgroup is the smallest normal subgroup of G from which we can hope to build a geometry over the quotient group G/ In(G). We say that G is a geometric group if In(G) is trivial.This paper is a discussion of a conjecture which states that every geometric group G of finite Morley rank is definably linear over a ring K1 ⊕…⊕ Kn where K1,…,Kn are some interpretable fields. This linearity conjecture seems to generalize the Cherlin–Zil'ber conjecture in a very large class of groups of finite Morley rank.We show that, if this linearity conjecture is true, then there is a Rosenlicht theorem for groups of finite Morley rank, in the sense that the quotient group of any connected group of finite Morley rank by its hypercentre is definably linear.
Дисертації з теми "Groupes de type fini":
1
Champetier, Christophe. "Propriétés génériques des groupes de type fini." Lyon 1, 1991. http://www.theses.fr/1991LYO10239.
Анотація:
Dans cette these, nous degageons les proprietes satisfaisantes par la majorite des groupes discrets. Nous etudions deux espaces de groupes: l'espace (denombrable) des groupes de presentation finie et l'espace (non denombrable) des groupes de type fini. Pour chacun d'eux, introduisons une notion de genericite adaptee, statistique dans le premier cas, topologique dans le second. Les presentations de groupes a deux relateurs sont presque surement hyperboliques, sans torsion et de dimension cohomologique 2. Par contre, l'espace des groupes de type fini possede une infinite non denombrable de groupes infinis a deux generateurs, dont tous les elements sont de torsion et uniformement parfaits. Cette etude a ete motivee par la decouverte de m. Gromov des groupes hyperboliques et les preuves des resultats de m. Gromov constituent l'ossature de cette these
2
Lasserre, Clément. "Sur les groupes de type fini : primalité, axiomatisabilité quasi finie et bi-interprétabilité avec l'arithmétique." Paris 7, 2011. http://www.theses.fr/2011PA077112.
Анотація:
Cette thèse concerne la théorie des modèles des groupes de type fini, sous l'angle des notions de primalité, d'axiomatisabilité quasi finie et de bi-interprétabilité avec l'arithmétique. Dans le chapitre 2, les groupes polycycliques-par-finis QFA sont caractérisés de façon purement algébrique. Nous voyons que ce sont exactement les groupes polycycliques-par-finis premiers. De plus, nous montrons que le nombre de Hirsch est « définissable ». Le chapitre 3 contient des investigations sur les produits directs de groupes QFA. Le problème est ramené à des questions sur les extensions centrales. Dans le chapitre 4, nous montrons que les groupes F et T de Thompson sont bi-interprétables avec l'arithmétique, donc sont QFA et premier. Ceci fournit le premier exemple d'un groupe simple QFA et premierThe thesis is about the model theory of finitely generated groups, with a view toward the notions of primality, quasi-finite axiomatizability and bi-interpretability with the arithmetic. In Chapter 2, polycyclic-by-finite QFA groups are characterized in a purely algebraic way. We also obtain that they are exactly the polycyclic-by-finite prime groups. Further, we show that the Hirsch number is definable. In Chapter 3, we investigate direct products of QFA groups. The problem is identified as a question on central extensions. In Chapter 4, we show that Thompson's groups F and T are bi-interpretable with the arithmetic, so are QFA and prime. This give the first example of such a simple group
3
Dat, Jean-François. "Représentations (modulaires) de type fini de groupes p-adiques." Paris 7, 2000. http://www.theses.fr/2000PA077252.
4
Mathéus, Frédéric. "Probabilités et géométrie dans certains groupes de type fini." Habilitation à diriger des recherches, Université de Bretagne Sud, 2011. http://tel.archives-ouvertes.fr/tel-00919399.
Анотація:
Dans de nombreux phénomènes régis par le hasard, le résultat de l'observation provient de la combinaison aléatoire d'événements élémentaires : le gain d'un joueur au jeu de pile ou face est le résultat de parties successives, mélanger un jeu de cartes s'effectue en plusieurs battages consécutifs, l'enchevêtrement d'une molécule d'ADN dans une cellule est le produit, entre autres, de croisements successifs. Ces événements élémentaires ont la particularité d'être réversibles (gagner/perdre au pile ou face, croiser/décroiser des brins d'ADN) et l'aléa régissant leur combinaison possède une certaine indépendance (l'issue d'une partie de pile ou face n'a a priori aucune influence sur la suivante). Un modèle possible pour ces phénomènes consiste à considérer un groupe G, fini ou dénombrable, que l'on munit d'une mesure de probabilité μ. On effectue des tirages successifs d'éléments dans G avec les hypothèses suivantes : les tirages sont indépendants, et, pour chaque tirage, μ(g) est la probabilité de tirer l'élément g. Si g1, g2,...,gn est le résul- tat de n tirages, on forme le produit g1.g2. ... . gn. C'est, par définition, la position à l'instant n de la marche aléatoire sur G de loi μ, et la question est : que peut-on dire du comportement asymptotique de g1.g2. ... .gn lorsque n augmente in- définiment ? La marche aléatoire s'en va-t'elle à l'infini ? Si oui, dans quelle direction ? Et à quelle vitesse ? Mes travaux depuis 2003 sont consacrés, pour l'essentiel, à l'étude du comportement asymptotique des marches aléatoires dans trois familles de groupes infinis, non abéliens et de type fini : les produits libres de groupes finis, les groupes d'Artin diédraux, ainsi que certaines extensions des groupes libres. Ils sont le fruit de collaborations avec Jean Mairesse (CNRS, Paris VI) et François Gautero (Université de Nice). Dans le cas des produits libres de groupes finis, nous décrivons précisément la mesure harmonique pour les marches aléatoires au plus proche voisin dans ces groupes, ce qui permet de calculer la vitesse et l'entropie asymptotique. En particulier, ces quantités dépendent de façon analytique des coefficients de μ. Considérant l'inégalité fondamentale de Yves Guivarc'h entre vitesse, entropie et croissance, nous montrons que les générateurs canoniques des produits libres de groupes finis sont extrémaux au sens de Vershik. Les groupes d'Artin diédraux forment une classe de groupes d'Artin qui généralise le groupe de tresses à trois brins B3 et pour laquelle nous donnons une description précise des géodésiques. La connaissance de la vitesse de fuite des marches aléatoires au plus proche voisin dans le groupe B3 est un premier outil de mesure de la complexité asymptotique d'une tresse aléatoire. Dans ce cas, on montre que la vitesse dépend de façon lipschitzienne mais non différentiable de μ, faisant apparaître certaines transitions de phase. Enfin, en ce qui concerne les extensions du groupe libre, nous montrons que, dans certains cas (comprenant notamment les extensions cycliques) les fonctions μ-harmoniques bornées sont entièrement décrites via le bord du groupe libre sous-jacent. La preuve repose sur l'existence d'actions non triviales de ces groupes sur des arbres réels, couplée à des critères généraux sur les compactifications des groupes développés par Vadim Kaimanovich.
5
Deloro, Adrien. "Groupes simples connexes minimaux de type impair." Phd thesis, Université Paris-Diderot - Paris VII, 2007. http://tel.archives-ouvertes.fr/tel-00756728.
Анотація:
Le but de la thèse est l'étude de certains "petits" groupes de rang de Morley fini. La conjecture de Cherlin-Zilber affirme que les groupes simples infinis de rang de Morley fini sont algébriques. Dans le cadre d'une approche inductive, "petit" doit signifier simple et minimal, dans le sens où le groupe ambiant est simple mais que toute section propre connexe en est résoluble. Le seul tel groupe algébrique est PSL2 ; la thèse est vouée à reconnaître ce groupe sous certaines hypothèses supplémentaires, et à limiter les pathologies sinon. On s'est placé en type impair, ce qui revient à attendre un corps (algébriquement clos) de caractéristique impaire ou nulle. L'identification de PSL2 (chapitre 3) ainsi que l'étude des éventuelles configurations non-algébriques (chapitre 5) repose essentiellement sur une notion d'unipotence en caractéristique nulle introduite par Burdges. Celle-ci permet dans le contexte simple connexe minimal de nombreux lemmes de rigidité, offrant ainsi une théorie complexe mais puissante des intersections de sous-groupes de Borel.
6
Bitar, Nicolás. "Subshifts of Finite Type on Groups : Emptiness and Aperiodicity." Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASG034.
Анотація:
Un sous-décalage de type fini est un ensemble de pavages d'un groupe sujet à un nombre fini de contraintes locales, où le groupe agit par translation. Ces dernières années, de nombreux progrès ont été réalisés dans la compréhension de leurs propriétés dynamiques et calculatoires. Le but de cette thèse est de poursuivre cette étude sur la manière dont les propriétés algébriques et géométriques du groupe sous-jacent influencent les propriétés des sous-décalages de type fini définis sur le groupe. Les résultats sont regroupés en trois grandes catégories : décidabilité, apériodicité et substitutions. Dans la première partie, nous étudions le problème du domino, ses variantes, et les conséquences de son indécidabilité sur de nombreux groupes de type fini. Nous classifions la calculabilité du Problème du Domino à Première Tuile Fixée, du Problème du Domino Récurrent, du Problème k-SAT, et des Problèmes du Domino Serpent pour de nombreuses classes de groupes bien connues. En particulier, ils sont tous décidables pour des groupes virtuellement libres. Cette classification est obtenue par des réductions utilisant des constructions SFT, la théorie des automates, et la logique monadique du second ordre. A la fin de la première partie, nous prenons une tangente pour étudier l'ensemble des marches auto-évitantes bi-infinies sur les graphes de Cayley. Cet ensemble apparaît naturellement dans l'étude du problème du serpent infini et est un sous-décalage de ℤ. Nous classifions les groupes pour lesquels ce sous-décalage est apériodique, de type fini, et sofique. Nous étudions également son entropie et sa relation avec la constante connective du graphe de Cayley. La deuxième partie traite de l'existence de sous-décalages de type fini fortement et faiblement apériodiques. Nous commençons par une étude de l'état de l'art de ces problèmes et explorons les parallèles avec des problèmes de probabilité et de combinatoire. Nous examinons ensuite quels sous-groupes d'un groupe peuvent être réalisés en tant que stabilisateurs de sous-décalages de type fini, en établissant des conditions algébriques et calculatoires pour que cela se produise. Dans ce même cadre, nous introduisons la classe des groupes périodiquement rigides, c'est-à-dire des groupes où chaque sous-décalage de type fini faiblement apériodique est fortement apériodique. Nous terminons cette partie en construisant, à partir des travaux d'Aubrun et de Kari, les premiers exemples de sous-décalages de type fini fortement apériodiques sur des groupes de Baumslag-Solitar non résolubles et sur Fₙ x ℤ. Par des théorèmes de Whyte et Cohen, nous obtenons l'existence de tels sous-décalages pour les groupes de Baumslag-Solitar généralisés non cycliques. La dernière partie de cette thèse introduit de nouvelles notions de substitutions, de systèmes S-adiques, et leurs sous-décalages correspondants pour les groupes dénombrables. Nous identifions trois classes de groupes. Premièrement, nous définissons les groupes S-décomposables. Ces groupes ont la structure hiérarchique appropriée pour définir des systèmes S-adiques généraux. Deuxièmement, nous étudions les groupes ccc introduits par Gao, Jackson et Seward, car ils permettent de définir des systèmes S-adiques à forme constante. Troisièmement, nous introduisons les groupes monoformes. Ces groupes permettent de définir des substitutions à forme constante. Nous fournissons des exemples pour les trois classes et des exemples pour leurs systèmes S-adiques correspondants. Nous terminons par l'étude des propriétés dynamiques des sous-décalages définis par ces systèmes. Nous montrons qu'en général, ils sont minimaux sous des conditions de primitivité, et que pour certains groupes ccc moyennables, ils ont une entropie nulle et sont uniquement ergodiquesA subshift of finite type is a set of tilings of a group subject to a finite number of local constraints, where the group acts by translation. In recent years, much progress has been made in understanding their dynamical and computational properties. The goal of this thesis is to continue the study of how the algebraic and geometric properties of the underlying group influence the properties of subshifts of finite type defined on the group. The results are divided into three broad categories: decidability, aperiodicity, and substitutions. For the first part, we study the Domino Problem, its variants, and the consequences of its undecidability on many finitely generated groups. We classify the computability of the Seeded Domino Problem, the Recurring Domino Problem, the k-SAT Problem, and Domino Snake Problems for many well-known classes of groups. In particular, they are all decidable for virtually free groups. This classification is obtained through reductions involving SFT constructions, automata theory, and Monadic Second Order Logic. At the end of the first part, we go on a tangent to study the set of bi-infinite self-avoiding walks on Cayley graphs. This set appears naturally in the study of the Infinite Snake Problem and is a ℤ-subshift. We classify for which groups this subshift is aperiodic, of finite type, and sofic. We also study its entropy and its relation to the connective constant of the Cayley graph. The second part tackles the existence of strongly and weakly aperiodic subshifts of finite type. We begin with a survey on the state of the art of these problems and explore parallels with problems from probability and combinatorics. We then look at which subgroups of a group can be realized as the stabilizers of subshifts of finite type, establishing both algebraic and computational conditions for this to happen. Within this same framework, we introduce the class of periodically rigid groups, i.e. groups where every weakly aperiodic subshift of finite type is strongly aperiodic. We end this part by building upon the work of Aubrun and Kari to construct the first examples of strongly aperiodic subshifts of finite type on non-solvable Baumslag-Solitar groups and on Fₙ x ℤ. By theorems of Whyte and Cohen, we obtain the existence of such subshifts for non-cyclic generalized Baumslag-Solitar groups. The final part of the thesis introduces new notions of substitutions, S-adic systems, and their corresponding subshifts for countable groups. We identify three classes groups. First, we define S-decomposable groups. These groups have the appropriate hierarchical structure for defining general S-adic systems. Second, we study ccc groups introduced by Gao, Jackson, and Seward, as they allow the definition of constant-shape S-adic systems. Third, we introduce monoform groups. These groups allow for the definition of constant-shape substitutions. We provide examples for all three classes and examples for their corresponding S-adic systems. We finish studying the dynamical properties of the subshifts defined by these systems. We show that, in general, they are minimal under primitivity conditions, and that for some amenable ccc groups, they have zero entropy and are uniquely ergodic
7
Auclair, Emmanuel. "Les Surfaces et invariants de type fini en dimension 3." Phd thesis, Université Joseph Fourier (Grenoble), 2006. http://tel.archives-ouvertes.fr/tel-00113863.
Анотація:
Cette thèse porte sur les invariants des sphères d'homologie entière de dimension 3, et en particulier sur les invariants de type fini pour la filtration de Goussarov-Habiro.Dans une première partie, on étudie la variation d'un invariant de degré 2n après chirurgie le long d'une surface par un élément du 2n-ième terme de la série centrale descendante du groupe de Torelli. Dans le cas d'un commutateur de 2n éléments du groupe de Torelli, on exprime cette variation en fonction de l'homomorphisme de Johnson évalué sur ces 2n éléments et du système de poids de l'invariant.
Le calcul des claspers de Goussarov-Habiro donne des équivalences topologiques entre des chirurgies sur des corps en anses plongés dans les variétés. Ce calcul a déjà permis de préciser le comportement des invariants de type fini lors de nombreuses modifications topologiques. La deuxième partie de cette thèse est consacrée à un raffinement de ce calcul. Ce raffinement est ensuite appliqué à l'obtention d'une formule de chirurgie géométrique sur les noeuds pour les invariants de degré 4, c'est-à-dire que l'on exprime la variation d'un tel invariant après chirurgie sur un noeud en fonction d'invariants de courbes tracées au voisinage d'une surface de Seifert de ce noeud.
8
Chaneb, Reda. "Basic sets and decomposition matrices of finite groups of Lie type in small characteristic." Thesis, Université de Paris (2019-....), 2019. http://www.theses.fr/2019UNIP7166.
Анотація:
Cette thèse se concentre sur les aspects modulaires de la théorie des représentations. Plus précisément, nous nous intéressons aux ensembles basiques des blocs unipotents des groupes finis de type de Lie qui vérifient une propriété d’ « unitriangularité ». Dans la première partie de cette thèse , en nous inspirant des travaux de Lusztig sur le paramétrage des représentations unipotentes en caractéristique 0, nous introduisons une méthode pour compter les représentations modulaires irréductibles contenues dans les blocs unipotents. Nous conjecturons que cette méthode est valable pour tout les groupes finis de type de Lie définis sur un corps dont la caractéristique est bonne et nous montrons que la conjecture est vraie dans un certain nombre de cas. La seconde partie de cette thèse a consisté à généraliser les résultats de Geck sur l’existence d’ensemble basiques unitriangulaire pour les 2-blocs unipotents des groupes classiques au cas ou le centre est non connexe. Le dernier aspect de cette thèse porte sur les matrices de décomposition des groupes finis de type de Lie dans le cas de mauvais nombres premier. Nous obtenons des résultats pour le groupe le groupe Sp4(q) et le groupe exceptionnel G2(q)This thesis is focused on the modular aspect of representation theory. More precisely, we are interisted in basic sets for unipotent blocks of finite groups of Lie typ which are « unitriangular ». In the first part of the thesis, following Lusztig’s work on the parametrisation of unipotent representations in characeristic , we introduce a method to count irreducible modular representations lying in unipotent blocks. We conjecture that our method holds for every finite groups of Lie type defined over a field of good characteristic and we verify our conjecture in many cases. The second part of the thesis consists to generalize results of Geck on the existence of unitriangular basic sets for unipotent 2-blocks of classical groups to the case where the center is disconnected. The last aspect of the thesis is the computation of decomposition matrices of finite groups of Lie type for bad primes. We got results for Sp4(q) and G2(q)
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Massuyeau, Gwénaël. "Quelques aspects de la théorie des invariants de type fini en topologie de dimension trois." Habilitation à diriger des recherches, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00734378.
Анотація:
En topologie de dimension trois, les invariants de type fini se caractérisent par leur comportement polynomial vis-à-vis de certaines opérations chirurgicales qui préservent l'homologie des variétés. Motivée par l'approche perturbative des "invariants quantiques", la notion d'invariant de type fini a été initialement formulée par T. Ohtsuki qui en contruisit les premiers exemples ; les fondements théoriques des invariants de type fini ont ensuite été posés par plusieurs auteurs dont M. Goussarov et K. Habiro. Grâce à une construction de T. Le, J. Murakami & T. Ohtsuki basée sur l'intégrale de Kontsevich, on dispose pour les sphères d'homologie d'un invariant de type fini universel à valeurs diagrammatiques. Ce mémoire expose d'une manière synthétique certains aspects de la théorie des invariants de type fini, pour les variétés de dimension trois en général, et pour les cylindres d'homologie en particulier. Nous présentons notamment une extension fonctorielle de l'invariant LMO à une certaine catégorie de cobordismes, et nous appliquons ce foncteur à l'étude du monoïde des cylindres d'homologie. Nous expliquons comment nos constructions et résultats se relient aux travaux antérieurs de D. Johnson, S. Morita et R. Hain sur le groupe de Torelli d'une surface. Nous concluons par quelques problèmes et perspectives de recherche. Certains des travaux exposés dans ce mémoire ont été réalisés en collaboration avec D. Cheptea, K. Habiro et J.-B. Meilhan.
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Moutot, Etienne. "Autour du problème du Domino - Structures combinatoires et outils algébriques." Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEN027.
Анотація:
Étant donné un ensemble fini de tuiles carrés, le problème du domino est la question : «est-il possible de paver le plan entier en utilisant ces tuiles ?» Ce problème est connu pour être indécidable dans le cas des pavages du plan, et est très fortement lié à la question de la périodicité des pavages. Dans cette thèse nous abordons ce problème de deux point de vue différents:en regardant le cas particulier des pavages de faible complexité et en le généralisant aux structures plus généra les des groupes.Un pavage du plan est dit de faible complexité s'il y apparait moins de mn rectangles de taille m x n. Nivat conjecture en 1997 qu'un tel pavage est nécessairement périodique, avec comme conséquence que le problème du domino serait décidable pour les pavages de faible complexité. En continuant de développer des outils algébriques introduits par Kari et Szabados, nous prouvons une version généralisée de la conjecture de Nivat pour une classe de pavages particuliers (certains des sous-décalage algébrique). Nous parvenons également à montrer que la conjecture de Nivat est vraie pour tout pavage uniformément récurrent, avec comme conséquence que le problème du domino est effectivement décidable pour les pavages de faible complexité.Le problème du domino peut se formuler dans le cadre plus général des graphes de Cayley de groupes. Dans cette thèse nous développons de nouvelles techniques permettant de relier les graphes de Cayley de certains groupes à des graphes de substitutions.Une première technique nous permet de montrer qu'il existe à la fois des pavages fortement apériodiques et faiblement-non-fortement apériodiques pour les groupes de Baumslag-Solitar BS(l,n). Une seconde nous permet de montrer que le problème du domino est indécidable pour les groupes de surface, ce qui fourni une nouvelle classe de groupe vérifiant la conjecture disant que que le problème du domino d'un groupe est décidable si et seulement si le groupe est virtuellement libreGiven a finite set of square tiles, the domino problem is the question of whether is it possible ta tile the plane using these tiles.This problem is known to be undecidable in the planar case, and is strongly linked ta the question of the periodicity of the tiling.ln this thesis we look at this problem in two different ways: we look at the particular case of low complexity tilings and we generalize it to more general structures than the plane: groups.A tiling of the plane is sa id of low complexity if there are at most mn rectangles of size m x n appearing in it. Nivat conjectured in 1997 that any such tiling must be periodic, with the consequence that the domino problem would be decidable for low complexity tilings. Using algebraic tools introduced by Kari and Szabados, we prove a generalized version of Nivat's conjecture for a particular class of tilings (a subclass of what is called of algebraic subshifts). We also manage to prove that Nivat's conjecture holds for uniformly recurrent tilings, with the consequence that the domino problem is indeed decidable for low-complexity tilings.The domino problem can be formulated in the more general context of Cayley graphs of groups. ln this thesis, we develop new techniques allowing to relate the Cayley graph of some groups with graphs of substitutions on words.A first technique allows us to show that there exists bath strongly periodic and weakly-but-not strongly a periodic tilings of the Baumslag-Solitar groups BS(l,n).A second technique is used to show that the domino problem is undecidable for surface groups. Which provides yet another class of groups verifying the conjecture saying that the domino problem of a group is decidable if and only if the group is virtually free
Книги з теми "Groupes de type fini":
1
Enguehard, Michel. Révision dans les groupes finis: Groupes du type de Lie de rang 1. Paris: Société mathématique de France, 1986.
2
Enguehard, Michel. Révision dans les groupes finis: Groupes du type de Lie de rang I. Paris: Société mathématique de France, 1986.
3
Enguehard, Michel. Re vision dans les groupes finis: Groupes du type de Lie de rang 1. Paris: Socie te Mathe matique de France, 1986.
4
D'Adamo, James. The D'Adamo diet: A naturopath tells you how to unlock the energy, health, and vitality within you by matching your diet to your blood type. Toronto: McGraw-Hill Ryerson, 1989.
5
Artin, M., M. Demazure, and A. Grothendieck. Schemas en Groupes. Seminaire de Geometrie Algebrique du Bois Marie 1962/64 : II: Groupes de Type Multiplicatif, et Structure des Schemas en Groupes Generaux. Springer London, Limited, 2006.
6
Slavin, Sarah. U.S. Women's Interest Groups. Greenwood Publishing Group, Inc., 1995. http://dx.doi.org/10.5040/9798216028758.
Анотація:
No other reference analyzes the origins, development, programs, publications, and political action of 180 major American organizations concerned with women's issues in such depth. Over 100 experts give an overview of how national women's groups of all kinds and representing varied and broad segments of society have had an impact on a wide array of public policy issues in Washington in recent years. An introduction provides a content analysis, general background, and historical sketch for the profiles, which are arranged alphabetically. An appendix describes six government agencies of primary importance in handling women's issues, as agenda setters and bridges. A second appendix consists of the questionnaire which was sent to each organization covered in the volume. The alphabetically arranged profiles cover organizations with all types of goals and concerns, different racial and ethnic identification, church and temple affiliations: civil, elderly, professional, and occupational associations; social and sorority groups; labor and business organizations; not-for-profit and for-profit groups; research centers; and both partisan and nonpartisan organizations. Students, teachers, professionals in governmental and nongovernmental agencies, researchers, and citizen activists will find that this handy sourcebook is a treasury of authoritative information about how private citizens work to affect national policy and legislation in essential ways.
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Gardner, Lisa, and Kirsten Potter. Find Her. Brilliance Audio, 2016.
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Gardner, Lisa. Find Her. Ulverscroft Large Print Books, 2017.
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Gardner, Lisa. Find Her. Penguin Publishing Group, 2017.
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Gardner, Lisa. Find Her. Headline Publishing Group, 2016.
Частини книг з теми "Groupes de type fini":
1
Serre, Jean-Pierre. "Sous-groupes d’indice fini dans SL(n,Z)." In Springer Collected Works in Mathematics, 222–29. Berlin, Heidelberg: Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/978-3-642-37726-6_61.
2
Zayed, Maher. "Ultraproduits et modules sans facteurs directs de type fini." In Lecture Notes in Mathematics, 312–24. Berlin, Heidelberg: Springer Berlin Heidelberg, 1987. http://dx.doi.org/10.1007/bfb0078534.
3
Cauchon, Gérard. "Commutants des modules de type fini sur les algebres noetheriennes." In Lecture Notes in Mathematics, 109–17. Berlin, Heidelberg: Springer Berlin Heidelberg, 1986. http://dx.doi.org/10.1007/bfb0099508.
4
Becker, Florian, Mari Nygård, Jan Nygård, Age Smilde, and Evrim Acar. "Phenotyping of Cervical Cancer Risk Groups via Generalized Low-Rank Models Using Medical Questionnaires." In Communications in Computer and Information Science, 94–110. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-17030-0_8.
Анотація:
AbstractThe purpose of this study is to uncover cervical cancer (CC) risk phenotypes from self-reported lifestyle questionnaires and screening data. In general, computational phenotype discovery aims to find subgroups among individuals that share distinctive characteristics by analyzing electronic health records (EHR). This can benefit the understanding of a disease as well as uncover risk factors and provide possibilities for preventive action. The features in the women ($$n = 6359$$ n = 6359 ) by questionnaire features ($$p=29$$ p = 29 ) matrix with missing data are of different statistical data types (e.g., binary or ordinal data). We use so-called generalized low-rank models (GLRM) that can address this challenge via different statistical-data-type-dependent loss functions. We show that these models can uncover phenotypes related to cervical cancer risk factors from large-scale questionnaire data.
5
Lannes, Jean, and Saïd Zarati. "Tor et Ext-dimensions des H*V - A-modules instables qui sont de type fini comme H*V-modules." In Algebraic Topology: New Trends in Localization and Periodicity, 241–53. Basel: Birkhäuser Basel, 1996. http://dx.doi.org/10.1007/978-3-0348-9018-2_18.
6
Selmi, Mohamed. "Comparaison des semi-groupes et des résolvantes d’ordre α associés à des opérateurs différentiels de type divergence." In ICPT ’91, 15–45. Dordrecht: Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-011-1118-8_2.
7
Napal Fraile, María, Lara Vázquez Bienzobas, Isabel Zudaire Ripa, and Irantzu Uriz Doray. "The Effect of Adult Intervention in the Development of Science Process Skills." In Shaping the Future of Biological Education Research, 51–61. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-44792-1_4.
Анотація:
AbstractContrary to the commonly held belief that preschool children are not prepared to understand certain scientific phenomena, studies have shown at least an incipient command of science process skills (SPS) whenever children are provided with various opportunities and contexts for learning. Specifically, the degree of adult intervention may strongly determine learning outcomes, especially if this role consists of guiding exploration with productive questions that help the children focus their attention on the phenomena of interest. This research was aimed at assessing the impact of different styles of adult intervention on the learning of and engagement with science tasks, in the context of a proposal intended to develop SPS among young children. Forty-two children aged 4–6 were subdivided in three groups and participated in various science proposals under different styles of adult intervention: children-led, adult-led or scaffolded exploration. While the adult-led group attained the most detailed learning of concepts, the scaffolded exploration group improved their basic SPS more. The children-led intervention had the poorest results. The type of questions proved crucial, with productive questions which prompt the children to focus their attention or find a solution leading to much more accurate and complete answers.
8
Frønes, Tove Stjern, Maria Rasmusson, and Jesper Bremholm. "Equity and Diversity in Reading Comprehension—A Case Study of PISA 2000–2018." In Equity, Equality and Diversity in the Nordic Model of Education, 305–35. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-61648-9_12.
Анотація:
AbstractThis chapter studies equity in reading performance in PISA 2000–2018 in three Nordic countries: Denmark, Sweden and Norway. Using regression analyses, the study investigates how the reading performance trend for groups of students with different genders, home backgrounds and minorities has developed. The study is contextualised through an up-to-date description of reading comprehension instruction in the countries. In addition to trend analyses of general reading performance, the study examines if the differences between groups of students are consistent across different text formats in the digital version of the PISA test, distinguishing between static text types (e.g., articles, letters, stories) and dynamic text types (e.g., websites, forums and e-mails, etc.). We find a consistently high reading literacy performance in all Scandinavian countries compared with international development. There are large gender differences in the average reading performance in all three countries, disfavouring boys, especially low-performing boys from low SES home backgrounds. We find a huge and stable gap between minority and majority students’ reading achievement, even when corrected for SES. Taking these findings into account, we assert that there is no basis for concluding that the school systems give more equitable learning conditions for groups of students now than when the PISA assessments started. However, it appears that the new online text formats in PISA 2018 might shrink the differences between student groups. Based on our findings, we argue that it is highly doubtful if one can still speak of a Nordic model of education, both as an idea of equity and fairness and as a model that is united across the Nordic countries.
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Bahr, Ruth Huntley, Elaine R. Silliman, and Laura Conover. "Chapter 22. More than spelling accuracy." In Studies in Bilingualism, 586–612. Amsterdam: John Benjamins Publishing Company, 2024. http://dx.doi.org/10.1075/sibil.67.22bah.
Анотація:
Spelling is a linguistic process that integrates phonological, orthographic, and morphological knowledge into novel word forms. Regardless of language, students learn to identify meaningful sound/letter combinations as they learn how to spell. However, most spelling investigations only consider overall word accuracy and not the nature and number of linguistic features in error. This chapter illustrates the utility of a linguistic scoring procedure in documenting the nature of misspelling patterns longitudinally in two groups of students from grades 1–7 that varied by spelling ability. Quantitative and qualitative analyses of misspellings demonstrate how general word knowledge develops into specific word knowledge for spelling. This type of fine-grained linguistic analysis is useful in studying spelling skill in any alphabetic or alphasyllabary language.
10
Panisi, Martina, Ricardo F. de Lima, Jezreel do C. Lima, Yodiney dos Santos, Frazer Sinclair, Leonor Tavares, and David T. Holyoak. "Terrestrial Mollusca of the Gulf of Guinea Oceanic Islands." In Biodiversity of the Gulf of Guinea Oceanic Islands, 407–29. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-06153-0_16.
Анотація:
AbstractThe oceanic islands of the Gulf of Guinea are known for their remarkable endemic species richness, and the terrestrial Mollusca group is particularly distinctive. This chapter summarizes the exploration and diversity of this group, discussing biogeography, evolution, ecology, and conservation to identify persisting knowledge gaps. Terrestrial malacological studies in the Gulf of Guinea islands started at the end of the eighteenth century but have been intermittent. Recent systematic surveys have continued to find novelties, and the most recent revision lists 96 species, of which 62 are endemic: Príncipe has 40 terrestrial (60% single-island endemic) and five seashore species, São Tomé has 52 terrestrial (50% single-island endemic) and seven seashore species, Annobón has 14 terrestrial species (50% single-island endemic), 3 species are endemic to Príncipe and São Tomé, and 2 are endemic to the three islands. The islands were colonized by diverse “clades” arriving from continental Africa, which is consistent with biogeographical patterns from other taxonomic groups. However, in line with Mollusca dispersal limitations, inter-island colonization seems to be less frequent, while there are multiple cases of speciation within the same island. The land snail assemblage on São Tomé seems to be strongly structured by land-use type: endemics being associated mostly with forest and non-endemics to anthropogenically modified environments. Only 13 species have been recorded across the altitudinal range of São Tomé, suggesting altitude is also essential to determining species distribution. Habitat loss and introduced species are important threats, but so far, only the endemic Archachatina bicarinata has been listed as threatened. Despite recent progress, further studies are still needed to better understand this unique fauna and inform conservation strategies.
Тези доповідей конференцій з теми "Groupes de type fini":
1
GHEDAB, Mohamed El-Amine, Ikram EL ABBASSI, Rafik ABSI, and Moumen DARCHERIF. "Courbes de puissance pour une hydrolienne à axe vertical de type Darrieus en milieu fini." In Journées Nationales Génie Côtier - Génie Civil. Editions Paralia, 2020. http://dx.doi.org/10.5150/jngcgc.2020.058.
2
Galletti, Carlo, and Pietro Fanghella. "Kinematics of Special-Type Manipulators by Displacement-Groups." In ASME 2004 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/detc2004-57030.
Анотація:
After a brief summary of the basic aspects of displacement-group theory, several applications of this theory to the kinematics of robot mechanisms are described. Then, we show in greater detail how to obtain, in a simple way, the characteristic polynomials of manipulators with special structural parameters. The goal is to find the polynomials of degree two for these special-geometry manipulators. In our paper, we apply displacement-group theory to provide an elegant and compact presentation and discussion of this subject, and we demonstrate that some geometrical conditions on the shapes of the manipulator links, as stated in other scientific papers, can be eliminated without changing the degree of the characteristic polynomials.
3
Park, Jong-Po, Zili Xu, and Seok-Ju Ryu. "Fracture Analysis and Retrofit Design of 1st Stage Blades for a Low-Pressure Steam Turbine." In ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-41137.
Анотація:
Cracking of blade fingers occurred in a few numbers of 1st stage blades for low-pressure steam turbines. In order to find out the fault mechanism, one of the cracked blades has been inspected. The inspection results showed that the cracking blades has been inspected. The inspection results showed that the cracking of the blade finger was caused by high cycle fatigue. Vibratory modes of the blade group have been calculated and measured using a 3-D finite element S/W and impact test, respectively. The results showed that resonance of the second type group axial vibration mode with nozzle passing frequency was the source of high cycle fatigue load. To avoid the dangerous resonance, the blade groups have been modified into 10 blades per group. The new blade groups have been operated safely more than one year since the modification.
4
Saidi, M. H., and Amin Mehrabian. "Design Optimization of Diffuser Type Valveless Micropumps." In ASME 8th Biennial Conference on Engineering Systems Design and Analysis. ASMEDC, 2006. http://dx.doi.org/10.1115/esda2006-95104.
Анотація:
Valveless piezoelectric micropumps are in wide practical use due to their ability to conduct particles with absence of interior moving mechanical parts. In this paper, using finite element method, an extended numerical study on fluid flow through micropump chamber and diffuser valves is conducted to find out the optimum working conditions of micropump. In order to obtain maximum generality of the reported results, an analytical study along with a dimensional analysis is presented primarily, to investigate the main dimensionless groups of parameters affecting the micropump net flux. Consequently, the parameters appeared in the main dimensionless groups have been changed in order to understand how the pump rectification efficiency, defining as the ratio of micropump net flux to sum of the absolute values of fluxes of inlet and outlet valves, and optimum diffuser angle depend on these parameters. At last, a set of characteristic curves are constructed which show these dependencies. The optimum working condition of micropump can be clearly found out through the use of these general characteristic curves.
5
Adcock, Thomas A. A., and Paul H. Taylor. "Ocean Wave Non-Linearity and Wind Input in Directional Seas: Energy Input During Wave-Group Focussing." In ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/omae2018-77998.
Анотація:
There has been speculation that energy input (wind) can play an important role in the formation of rogue waves in the open ocean. Here we examine the role energy input can play by adding energy to the modified non-linear Schrödinger equation. We consider NewWave type wave-groups with spectra which are realistic for wind waves. We examine the case where energy input is added to the group as the wave-group focuses. We consider whether this energy input can cause significant non-linear effects to the subsequent spatial and spectral evolution. For the parameters considered here we find this to have only a small influence.
6
Журавлев, Д. В., and Г. А. Ломтадзе. "Fine Ware and Lamps from the Residence of Chrysaliskos." In Древности Боспора. Crossref, 2023. http://dx.doi.org/10.25681/iaras.2022.978-5-94375-372-5.59-100.
Анотація:
The Residence of Chrysaliskos is one of the most interesting Late Hellenistic fortified con structions, situated in the north-eastern part of the Taman Peninsula. It was excavated in 1970- 1973 by Nikolay Sokol’skiy. This house, which was a residence of a powerful Bosporan official during the reign of king Asandros, was destroyed in a great fire. In the layers of destruction, an important pottery assemblage was unearthed. The materials from the excavations have been preliminary published but without any special analysis of the ceramic complex. We could not distinguish exactly all the production centers of this pottery without ar chaeometric studies, but according to visual characteristics the main part of them belong to Bosporan sigillata, a local group of pottery distributed only in the Bosporan kingdom. Some Pergamene and Knidian vessels as well as their local imitations were also found here. A sepa rate group of pottery of the same shape as Bosporan sigillata was covered with black slip. Several lekythos and unguentaria are also present in the article. Lamps of jug-shape type, typical for the late Hellenistic period, are the most common group among lighting equipment. This article is the revised version of the publication in English in the volume of the Inter national Association for Research on Pottery of the Hellenistic Period (Lomtadze, Zhuravlev 2020). All the parallels for different pottery groups came from Crimea and Taman peninsula, as well as from other regions of the Black sea area and Mediterranean, mainly from the contexts of the second quarter of the 1st century BC From our point of view the Residence of Chrysaliskos could have been destroyed in the late third – early fourth quarter of the 1st century B.C., however it is still not evident what exact historic events could have caused such considerable devastation
7
Dahl Søndergaard, Bettina. "Lack of gender differences in engineering students’ assessment of group-based project exams." In SEFI 50th Annual conference of The European Society for Engineering Education. Barcelona: Universitat Politècnica de Catalunya, 2022. http://dx.doi.org/10.5821/conference-9788412322262.1128.
Анотація:
At Aalborg University in Denmark, engineering, science, and mathematics students usually spend half the time each semester working in groups on projects within a problem-based learning (PBL) curriculum. These projects are assessed through group-based exams where students receive individual grades. A previous survey of all engineering, science, and mathematics students showed significant differences in how they, respectively, view various aspects of the group exam. However, students also differ when comparing engineering programmes. This paper focuses on potential gender differences in perception of the group exam. Studies of other exam types showed, e.g., that female students report higher levels of text anxiety, have different reactions to exam pressure, and are less overconfident than male students. The present survey was answered by 915 students (617 males, 298 females) from all semesters and study programmes in engineering, science, and mathematics. The analysis showed that on the majority of questions, there were no significant differences between males and females. However, female students are significantly more in favour of an individual exam, and significantly more often experience they need to speak before having finished thinking. Significantly more male students find that participating with their peers during the group-quizzing phase of the exam gives a sense of security, and they are significantly more tactical about when to speak. The paper discusses the areas of significant differences among males and females and the areas without such differences, and concludes that a group exam might be a more gender neutral type of exam for engineering students.
8
Adcock, Thomas A. A., and Shiqiang Yan. "The Focusing of Uni-Directional Gaussian Wave-Groups in Finite Depth: An Approximate NLSE Based Approach." In ASME 2010 29th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2010. http://dx.doi.org/10.1115/omae2010-20993.
Анотація:
The non-linear changes to a NewWave type wave-group are helpful in developing our understanding of the non-linear interactions which can lead to the formation of freak waves. In addition, Gaussian wave-groups are used in model tests where it is useful to have a simple model for their non-linear dynamics. This paper derives a simple analytical model to describe the nonlinear changes to a wave-group as it focuses. This paper is an extension to finite depth of the theory developed for deep water in Adcock & Taylor (2009) (Proc. Roy. Soc. A 465(2110)). The model is derived using the conserved quantities of the cubic nonlinear Schrodinger equation (NLSE). In deep water there are substantial changes to the group shape and spectrum as the wave-group focuses, and the characteristics of these changes are governed by the Benjamin-Feir Index. However, in finite depth the characteristics of the non-linear interactions change, reducing the non-linear changes to the group shape. The analytical model is validated against simulations using the NLSE and against full potential flow solutions using a QALE-FEM numerical scheme. We also compare its predictions against experiments in a physical wavetank. We find that the NLSE, and thus analytical theories derived from it, capture the dominant physics in the evolution of narrowbanded wave-groups.
9
Xu, Jin, Jiaxu Yao, Pengfei Su, Jiang Lei, Junmei Wu, and Tieyu Gao. "Heat Transfer and Pressure Loss Characteristics of Pin-Fins With Different Shapes in a Wide Channel." In ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/gt2017-63761.
Анотація:
Convective heat transfer enhancement and pressure loss characteristics in a wide rectangular channel (AR = 4) with staggered pin fin arrays are investigated experimentally. Six sets of pin fins with the same nominal diameter (Dn = 8mm) are tested, including: Circular, Elliptic, Oblong, Dropform, NACA and Lancet. The relative spanwise pitch (S/Dn = 2) and streamwise pitch (X/Dn = 4.5) are kept the same for all six sets. Same nominal diameter and arrangement guarantee the same blockage area in the channel for each set. Reynolds number based on channel hydraulic diameter is from 10000 to 70000 with an increment of 10000. Using thermochromic liquid crystal (R40C20W), heat transfer coefficients on bottom surface of the channel are achieved. The obtained friction factor, Nusselt number and overall thermal performance are compared with the previously published data from other groups. The averaged Nusselt number of Circular pin fins is the largest in these six pin fins under different Re. Though Elliptic has a moderate level of Nusselt number, its pressure loss is next to the lowest. Elliptic pin fins have pretty good overall thermal performance in the tested Reynolds number range. When Re>40000, Lancet has a same level of performance as Circular, but its pressure loss is much lower than Circular. These two types are both promising alternative configuration to Circular pin fin used in gas turbine blade.
10
Zhai, Yuyao, Liang Chen, and Minghua Deng. "Realistic Cell Type Annotation and Discovery for Single-cell RNA-seq Data." In Thirty-Second International Joint Conference on Artificial Intelligence {IJCAI-23}. California: International Joint Conferences on Artificial Intelligence Organization, 2023. http://dx.doi.org/10.24963/ijcai.2023/552.
Анотація:
The rapid development of single-cell RNA sequencing (scRNA-seq) technologies allows us to explore tissue heterogeneity at the cellular level. Cell type annotation plays an essential role in the substantial downstream analysis of scRNA-seq data. Existing methods usually classify the novel cell types in target data as an “unassigned” group and rarely discover the fine-grained cell type structure among them. Besides, these methods carry risks, such as susceptibility to batch effect between reference and target data, thus further compromising of inherent discrimination of target data. Considering these limitations, here we propose a new and practical task called realistic cell type annotation and discovery for scRNA-seq data. In this task, cells from seen cell types are given class labels, while cells from novel cell types are given cluster labels. To tackle this problem, we propose an end-to-end algorithm framework called scPOT from the perspective of optimal transport (OT). Specifically, we first design an OT-based prototypical representation learning paradigm to encourage both global discriminations of clusters and local consistency of cells to uncover the intrinsic structure of target data. Then we propose an unbalanced OT-based partial alignment strategy with statistical filling to detect the cells from the seen cell types across reference and target data. Notably, scPOT also introduces an easy yet effective solution to automatically estimate the overall cell type number in target data. Extensive results on our carefully designed evaluation benchmarks demonstrate the superiority of scPOT over various state-of-the-art clustering and annotation methods.
Звіти організацій з теми "Groupes de type fini":
1
Eshed, Y., and Z. B. Lippman. Fine tuning the shoot and inflorescence architectures for improved tomato yield. Israel: United States-Israel Binational Agricultural Research and Development Fund, 2022. http://dx.doi.org/10.32747/2022.8134148.bard.
Анотація:
In this project, we are determining the contribution of different types of variations, in gene function and in gene regulation, to altered shoot architecture first, and to field performance in the next stage. We are using tomato as a target, but also as a model for many other crops. Our focus is on two different components of yield associated traits - shoot architecture and organization of the inflorescence. Our focus was on two types of regulators; 1) genes involved in florigen - antiflogen balance and the way they impact the shoot, and 2) genes involved in inflorescence branching and it this way, the way they impact the number of flowers produced by the plant. For the first class, we described our thoughts on that matter in a joint review (Eshed and Lippman, 2019) where we argued that annualization of short-lived vine plants such as tomato and soybean was their major adaptation for intensive modern farming. This annualization was achieved by introduction of mutations in the anti florigen gene SELFPRUNING, mutations that were also used to domesticate/adapt cotton, roses, strawberries and more (Eshed and Lippman, 2019). Indeed, introduction of this mutation and additional one in another antifloraigen gene SP5G into a vine type tomatoes resulted in compact, early yielding plants suitable for urban agriculture (Kwon et al., 2020 - please note that Yossi Capua, a former graduate student from the Eshed group is a coauthor of this study). The other side of this project, customized generation of large branched inflorescences, relied on ongoing collaboration between the two labs on genes like S and genes of the SEP clade, J2 and EJ2. We first showed that highly branched j2 ej2 inflorescences can be quantitatively modified by introduction of either null or naturally weak alleles of the TM3/STM3 gene cluster (Alonge et al., 2020). We next showed that variation in inflorescence branching can be obtained by customized interreference in selected promoter motifs of S, a gene that is otherwise essential at the seed stage (Hendelamn et al., 2021). Overall, our joint project provided some prime examples for targeted use of genome editing for the formation of valuable alleles that can either improve modern crops or, significantly, open the door for rapid "domestication" of orphan crops
2
López Boo, Florencia, Jane Leer, and Akito Kamei. Community Monitoring Improves Public Service Provision at Scale: Experimental Evidence from a Child Development Program in Nicaragua. Inter-American Development Bank, November 2020. http://dx.doi.org/10.18235/0002869.
Анотація:
Expanding small-scale interventions without lowering quality and attenuating impact is a critical policy challenge. Community monitoring overs a low-cost quality assurance mechanism by making service providers account-able to local citizens, rather than distant administrators. This paper provides experimental evidence from a home visit parenting program implemented at scale by the Nicaraguan government, with two types of monitoring: (a) institutional monitoring; and (b) community monitoring. We find d a positive intent-to-treat effect on child development, but only among groups randomly assigned to community monitoring. Our findings show promise for the use of community monitoring to ensure quality in large-scale government-run social programs.
3
González, Andrea, Juan Carlos Hallak, Tatiana Soria Genta, and Peter K. Schott. Insertion of Argentine Firms in Global Value Chains Not Oriented to the Mass Market: The Cases of High-End Footwear and The Basso Group. Inter-American Development Bank, November 2012. http://dx.doi.org/10.18235/0012205.
Анотація:
This paper describes experiences of international insertion of Argentine producers of manufactured goods not oriented to the mass market. Based on these experiences, we develop a typology of potential alternatives of international insertion for this type of goods centered on the role of local agentsin design activities. Our analysis follows the global value chain (GVC) approach and emphasizes the links between local producers and buyers in developed countries. First, we analyze experiences of international insertion of producers and marketers of high end footwear. These cases involve high quality products that are intensive in original design. Second, we analyze various forms of international insertion of a single producer of valves for combustion engines, which primarily involve customized products. Despite the differences between these two industries, we find notable similarities in the forms of insertion they both present and in the knowledge requirements they impose on local producers.
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Martínez Jorge, Angel, and Javier Martínez Santos. Heterogeneous response and spillover effects of SSB taxes. Esade EcPol, March 2023. http://dx.doi.org/10.56269/20230327/amj.
Анотація:
In this paper we evaluate the taxation of sugar-sweetened and edulcorated beverages by using the natural quasi-experiment in Spain: in 2021 an increase in Value Added Tax was introduced in all regions of Spain except for some of them, which do not have VAT. These regions serve as a control group offering a unique opportunity in the literature for two reasons, the guarantee of avoiding cross-border consumer movements due to their geographical location and the opportunity to have a household consumption database with a rich set of characteristics. We find a pass-through of the tax to prices of over 95\% and a fall in soft drink consumption of 15\% among the poorest tertile of households, especially among those with children aged 5-16. In addition, we find a significant reduction in spending on unhealthy complementary goods among the same households in the first tertile. However, the remaining households did not react to the tax by reducing either their consumption of soft drinks or their consumption of complementary goods. Our results show the importance of considering the structure and economic capacity of the household, as well as the response of the consumption of complementary goods, when assessing the effect of this type of tax on consumption.
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Lora, Eduardo. Health Perceptions in Latin America. Inter-American Development Bank, December 2011. http://dx.doi.org/10.18235/0011373.
Анотація:
This is the first study that uniformly analyzes health perceptions in all of Latin America and tests in a systematic way their relation to economic conditions at the country, income group and individual levels. The study uses three types of health self-assessment questions: i) health satisfaction; ii) health status on a scale of 0- 10; and iii) the EuroQol 5D instrument (EQ-5D), which asks about mobility, self- care, usual activities, pain/discomfort, and anxiety/depression. The empirical analysis finds support for the hypothesis that cultural differences between countries prevent cross-national comparisons of health perceptions, but it does not find support for the widely held view that the same applies within countries, presumably because the poor are more tolerant of their health problems.
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Katzir, Nurit, Rafael Perl-Treves, and Jack E. Staub. Map Merging and Homology Studies in Cucumis Species. United States Department of Agriculture, September 2000. http://dx.doi.org/10.32747/2000.7575276.bard.
Анотація:
List of original objectives (1) Construct a saturated map of melon, using RFLP, SSR, RAPD and Inter-SSR genetic markers. (2) Study the homology between the genomes of cucumber and melon. (3) Add to the Cucumis map, biologically important genes that had been cloned in other plant systems. Background Cucumber and melon are important vegetable crops in Israel and the US. Genome analysis of these crops has lagged behind the major plant crops, but in the last few years genetic maps with molecular markers have been developed. The groups that participated in this program were all involved in initial mapping of cucurbit crops. This grant was meant to contribute to this trend and promote some of the more advanced applications of genome analysis, i.e., map saturation and comparative mapping between cucurbit species. Major achievements The main achievements of the research were (a) the construction of melon maps that include important horticultural traits and Resistance Gene Homologues, (b) the development of approximately 200 SSR markers of melon and cucumber, (c) the preliminary map merging of melon maps and of comparative mapping between melon and cucumber. Implications As a result of this program, we have a good estimate of the applicability of different types or markers developed in one cucurbit species to genetic mapping in other species. Since the linkage groups of melon and cucumber can now be related to each other, future identification of important genes in the two crops will be facilitated. Moreover, the further saturation of the maps with additional markers will now allow us to target several disease resistance loci, horticultural traits for marker-assisted selection, fine mapping and positional cloning.
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Colomb, Claire, and Tatiana Moreira de Souza. Regulating Short-Term Rentals: Platform-based property rentals in European cities: the policy debates. Property Research Trust, May 2021. http://dx.doi.org/10.52915/kkkd3578.
Анотація:
Short-term rentals mediated by digital platforms have positive and negative impacts that are unevenly distributed among socio-economic groups and places. Detrimental impacts on the housing market and quality of life of long-term residents have been particular contentious in some cities. • In the 12 cities studied in the report (Amsterdam, Barcelona, Berlin, Brussels, Lisbon, London, Madrid, Milan, Paris, Prague, Rome and Vienna), city governments have responded differently to the growth of short-term rentals. • The emerging local regulations of short-term rentals take multiple forms and exhibit various degrees of stringency, ranging from rare cases of laissez-faire to a few cases of partial prohibition or strict quantitative control. Most city governments have sought to find a middle-ground approach that differentiates between the professional rental of whole units and the occasional rental of one’s home/ primary residence. • The regulation of short-term rentals is contentious and highly politicised. Six broad categories of interest groups and non-state actors actively participate in the debates with contrasting positions: advocates of the ‘sharing’ or ‘collaborative’ economy; corporate platforms; professional organisatons of short-term rental operators; new associations of hosts or ‘home-sharers’; the hotel and hospitality industry; and residents’ associations/citizens’ movements. • All city governments face difficulties in implementing and enforcing the regulations, due to a lack of sufficient resources and to the absence of accurate and comprehensive data on individual hosts. That data is held by corporate platforms, which have generally not accepted to release it (with a few exceptions) nor to monitor the content of their listings against local rules. • The relationships between platforms and city governments have oscillated between collaboration and conflict. Effective implementation is impossible without the cooperation of platforms. • In the context of the European Union, the debate has taken a supranational dimension, as two pieces of EU law frame the possibility — and acceptable forms — of regulation of online platforms and of short-term rentals in EU member states: the 2000 E-Commerce Directive and the 2006 Services Directive. • For regulation to be effective, the EU legal framework should be revised to ensure platform account- ability and data disclosure. This would allow city (and other ti ers of) governments to effectively enforce the regulations that they deem appropriate. • Besides, national and regional governments, who often control the legislative framework that defines particular types of short-term rentals, need to give local governments the necessary tools to be able to exercise their ‘right to regulate’ in the name of public interest objectives.
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Dimaranan, Betina, Thomas Hertel, and Roman Keeney. OECD Domestic Support and the Developing Countries. GTAP Working Paper, January 2003. http://dx.doi.org/10.21642/gtap.wp19.
Анотація:
This paper aims to shed light on the potential interests of developing countries in reforms to domestic support for agriculture in the OECD economies. In order to accomplish this goal, we begin by reviewing the literature on the impacts of domestic support on key variables, including farm income, in the OECD economies themselves. We then proceed to revise the standard GTAP model of global trade, based on recent work at the OECD, in order to permit it to better capture these impacts. A series of stylized simulations are subsequently offered to illustrate the differential impacts of alternative types of domestic support. These suggest the possibility of policy re-instrumentation, whereby farm income is stabilized in the face of cuts to overall support levels by shifting the mix of subsidies away from the more trade-distorting instruments which also tend to be ineffective tools for boosting farm incomes. We then explore in considerable detail the mechanisms by which OECD agricultural reforms affect developing country welfare. The primary channel for such effects works through the terms of trade which in turn depend in part on whether a country is a net exporter or a net importer of the affected OECD products. Long term support for agricultural program commodities in OECD countries, coupled with relative taxation in many developing countries, has left the latter increasingly dependent on imports of these subsidized products. This has, in turn, made them more vulnerable to agricultural reforms that raise these prices. As a result, we find that an across-the-board, 50% cut in all domestic support for OECD agriculture leads to welfare losses for most of the developing regions, as well as for the combined total group of developing countries. The 50% cut in domestic support also results in large declines in farm incomes in Europe, and, to a lesser degree, North America. This makes such a reform package an unlikely political event. An alternative approach to reforming agricultural policies in the OECD would be to focus on broad-based reductions in market price support. This has already been occurring in the EU, in particular, where domestic support has increasingly replaced border measures. As demonstrated in this paper, the basic economic principles of agricultural support policies suggest that a shift from market price support to land-based payments could generate a “win-win” outcome whereby farm incomes are maintained and world price distortions are reduced. This is the direction charted by the OECD in its recent “Positive Reform Agenda” for agriculture. We formally examine such an agricultural reform scenario, implementing a 50% cut in market price support for OECD agriculture, with a compensating set of land payments designed to maintain farm income in each of the member economies. This comprehensive reform scenario results in increased welfare for most developing countries, with gains on other commodities offsetting the terms of trade losses from higher program crop prices. We conclude that developing countries will be well advised to focus their efforts on improved market access to the OECD economies, while permitting these wealthy economies to continue – indeed even increase – domestic support payments. Provided these increased domestic support payments are not linked to output or variable inputs, the trade-distorting effects are likely to be small, and they can be a rather effective way of offsetting the potential losses that would otherwise be sustained by OECD farmers. This type of policy re-instrumentation will increase the probability that such reforms will be deemed politically acceptable in the OECD member economies, while simultaneously increasing the likelihood that such reforms will also be beneficial to the developing economies.
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Hertel, Thomas, Maros Ivanic, Paul Preckel, and John Cranfield. Trade Liberalization and the Structure of Poverty in Developing Countries. GTAP Working Paper, April 2003. http://dx.doi.org/10.21642/gtap.wp25.
Анотація:
“Globalization increases poverty” is a common assertion made by critics of globalization. The proliferation of low-wage jobs and higher food prices are some of the arguments brought forward in support of this argument. One of the hallmarks of globalization is the systematic dismantling of barriers to trade. Advocates of trade liberalization – particularly industrialized country agriculture reform – argue that the ensuing rise in world prices for agriculture products will boost rural incomes, thereby reducing poverty in the poorest countries, where the bulk of world poverty resides. Who is right? The goal of this paper is take a systematic look at the structure of poverty across a range of developing countries in Africa, Asia and Latin America, and explore how national poverty rates in some of the poorest countries in the world are likely to be affected by global trade liberalization. Our analysis of the structure of poverty is based on national household surveys from 14 developing countries. While we consider both spending and earnings effects of trade liberalization, it is argued that the earnings effects will generally be the dominant factor. This is particularly true in the short run for households that are highly specialized in their earnings patterns. Consider the case of a self-employed farm household. Assuming that trade liberalization results in higher farm prices, we expect the short run effect on the returns to family labor and land to be positive, and somewhat larger in percentage terms (the so-called “magnification effect”). Furthermore, if this household is not employed off-farm, then the farm profitability effect translates directly into an income effect, and this is likely to be sufficient to lift some of the farm households out of poverty. Of course this same effect can work in reverse, with commodity price declines increasing poverty. This makes specialized households highly vulnerable to trade policy shocks. In addition to agriculture-specialized households, we focus on self-employed non-agriculture specialized households, households specialized in wage labor and those relying on transfer payments for 95% or more of their income. Together, these four types of specialized households account for an average of 56% of the poor in the 14 countries examined. Thus a majority of the poor have specialized earnings patterns and are likely to be disproportionately affected by trade liberalization. The same is not true of the non-poor, where a majority of the households are diversified, and are therefore less vulnerable to sector-specific commodity price changes. We also find that the poor are over-represented among the agriculture-specialized households. With this background, we turn to an examination of the broad effects of multilateral trade liberalization on relative commodity prices and factor returns across the 14 countries in question. We distinguish between per capita effects – or the impact of trade liberalization on the “average” household in each country, and the effects on the poorest households. Our per capita results are quite similar to other studies of multilateral trade liberalization, with most countries gaining modestly, while a few gain substantially and a few lose due to the erosion of benefits from existing preferences. Some argue that this “rising tide will lift all boats” and so the positive per capita gains from trade liberalization will reduce poverty. However, we show that the short run impact of trade liberalization on different household groups is quite varied, and not always positive. First of all, global trade liberalization tends to raise food prices – particularly for staples, relative to non-food prices. This is true in all but 2 of the countries in our sample. This food price hike has an adverse effect on the poor, relative to the per capita household, since they spend a disproportionate share of their income on food. Also, the short run earnings impacts are quite varied, with agricultural profits rising relative to per capita income in 11 of the 14 countries, while relative non-agricultural profits and wages fall in many of these countries. Thus the overall impact on poverty depends on the structure of poverty in each country – hence our emphasis on this topic. We proceed to systematically explore the impact of trade liberalization on poverty utilizing a recently developed analytical framework that combines the detailed household survey data with a global economic model in order to measure the poverty impacts of trade liberalization on the five different household strata in each country. Each of the first four strata corresponds to one of the groups of earnings-specialized households, while the fifth encompasses the diversified households in each country. We conduct our analysis at the level of one hundred income percentiles, ranging from poorest to richest in each stratum. In this way, we uncover the differential impact of trade liberalization, by country, stratum and by income level. We also calculate the change in poverty rates, both at the stratum and national levels. Our findings emphasize the differential short run poverty impacts of multilateral trade liberalization on poverty across countries, across strata, and within strata, thereby highlighting the links between the structure of poverty and the national impacts of trade liberalization.