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1

Kraus, Armin. "MRT-Leberdiagnostik mit dem leberspezifischen Kontrastmittel Gd-EOB-DTPA." Diss., lmu, 2003. http://nbn-resolving.de/urn:nbn:de:bvb:19-12753.

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2

Mucha, Bettina. "Mutationsanalyse bei 21 mut 0-Patienten mit Methylmalonylazidurie (MMA)." [S.l. : s.n.], 2001. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB9494927.

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3

Egbers, Nina [Verfasser]. "Multiparametrische MRT und MRT-gestützte Biopsie bei Patienten mit Prostatakarzinomverdacht : Nachweisgenauigkeit und Akzeptanz der MRT-gestützten Biopsie / Nina Egbers." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2016. http://d-nb.info/1113593032/34.

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4

Oppelt, Britta. "Nachuntersuchung von Patienten mit arthroskopisch subacromialer Dekompression in Korrelation mit Klinik, MRT und isokinetischen Kraftverhältnissen." [S.l.] : [s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=969418930.

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5

Kunz, Martin [Verfasser]. "Korrelation kognitiver Defizite mit MRT-volumetrischen Untersuchungen bei Patienten mit idiopathischem Parkinson-Syndrom / Martin Kunz." Ulm : Universität Ulm, 2020. http://d-nb.info/1223546241/34.

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6

Gemeinhardt, Ole. "Funktionelle Bildgebung der Vaskularisation und Perfusion des Prostatakarzinoms mit dynamischer MRT : Korrelation mit morphometrischen Parametern /." Berlin : Mbv, 2008. http://d-nb.info/990627349/04.

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7

Nikolova, Alexandrina D. "Aussagefähigkeit der MRT mit SPIO von atherosklerotischen Wandläsionen bei Kaninchen." [S.l.] : [s.n.], 2003. http://www.diss.fu-berlin.de/2003/204/index.html.

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8

Joppich, Constanze Elke. "MRT-axillärer Lymphknoten mit USPIO-Kontrastmittel histopathologische Korrelation und Wertigkeit /." [S.l.] : [s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=97018235X.

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9

Gemeinhardt, Ole [Verfasser]. "Funktionelle Bildgebung der Vaskularisation und Perfusion des Prostatakarzinoms mit dynamischer MRT : Korrelation mit morphometrischen Parametern / Ole Gemeinhardt." Berlin : Freie Universität Berlin, 2008. http://d-nb.info/1023258757/34.

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10

Goldoni, Luca. "Prime Numbers and Polynomials." Doctoral thesis, Università degli studi di Trento, 2010. https://hdl.handle.net/11572/368684.

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This thesis deals with the classical problem of prime numbers represented by polynomials. It consists of three parts. In the first part I collected many results about the problem. Some of them are quite recent and this part can be considered as a survey of the state of the art of the subject. In the second part I present two results due to P. Pleasants about the cubic polynomials with integer coefficients in several variables. The aim of this part is to simplify the works of Pleasants and modernize the notation employed. In such a way these important theorems are now in a more readable form. In the third part I present some original results related with some algebraic invariants which are the key-tools in the works of Pleasants. The hidden diophantine nature of these invariants makes them very difficult to study. Anyway some results are proved. These results make the results of Pleasants somewhat more effective.
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11

Schnier, Michael. "Validierung dreidimensionaler MRT-basierter Knorpelvolumen und -dickenmessungen mit der CT-Arthrographie." Diss., lmu, 2002. http://nbn-resolving.de/urn:nbn:de:bvb:19-5149.

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12

Palladino, Tanja. "MRT– Untersuchung des Amygdala-Volumens in Zusammenhang mit einer Major Depression." Diss., lmu, 2009. http://nbn-resolving.de/urn:nbn:de:bvb:19-98907.

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13

Sandahl, Anita. "Skolmatematiken - kultur eller myt? : mot en bestämning av matematikens didaktiska identitet /." Linköping : Univ, 1997. http://www.bibl.liu.se/liupubl/disp/disp97/ipp51s.htm.

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14

Mergner, Ulrike [Verfasser]. "Histopathologisch-radiologische Korrelation des Retinoblastoms mit der hochauflösenden MRT / Ulrike Mergner." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2008. http://d-nb.info/1022910450/34.

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15

Schmidt, Christoph [Verfasser]. "Quantitative MRT-Bildgebung bei Patienten mit idiopathischer intrakranieller Hypertension / Christoph Schmidt." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2015. http://d-nb.info/1071088750/34.

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16

Zhang, Shuai. "Physiological and Biochemical Aspects of Methionine Isomers and Precursors in Broilers." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/71816.

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Methionine (Met) is an essential amino acid for animals and also the first limiting amino acid in a broiler diet. The dietary supplemental Met sources include the natural isoform L-methionine (L-Met), the synthetic form DL-methionine (DL-Met) and the synthetic Met precursor DL-2-hydroxy-4 (methylthio)-butanoic acid (DL-HMTBA). The objective of this dissertation was to determine the effect of different dietary Met source supplementation and Met deficiency on a series of physiological and biochemical aspects, including growth performance, global DNA methylation and methyltransferase activity, blood antioxidant profile (e.g., acute phase protein, leukocyte count), intestinal nutrient transporter gene expression, Met converting enzyme gene expression and activity, oxidative stress markers, and a potential pathway related to amino acid signaling. To achieve this goal, male Cobb-500 broilers were raised from day of hatch (d0) to d35 post-hatch and fed a diet deficient in methionine and cysteine (Met + Cys) (control) or the same diet supplemented with 0.22% DL-Met, 0.22% L-Met or 0.31% DL-HMTBA (to provide 0.22% DL-Met equivalent) to meet Met + Cys requirements. Tissues (liver, breast muscle, duodenum, jejunum and ileum) and blood samples were collected at various ages from d0 to d35 for analysis. Met supplementation significantly improved body weight gain and feed efficiency compared to the Met deficient group, but no differences were observed among DL-Met, L-Met and DL-HMTBA for growth performance parameters (P > 0.05). Met supplementation had no effect on red blood cell packed cell volume, white blood cell differential count, hepatic total DNA methylation, DNA methyltransferase and Met oxidase activity, and had limited effects on activation of p70S6K, a key amino acid signaling protein (P > 0.05). Although dietary Met sources did not change oxidative status of the treated chickens, both L-Met and DL-Met but not DL-HMTBA supplementation decreased the level of acute phase protein serum amyloid A compared to the control group (P > 0.05). The effect of Met supplementation on gene expression of nutrient transporters and Met converting enzymes were complex and dynamic. Most of the target genes demonstrated tissue- and development-dependent expression patterns, with few significant treatment effects observed. L-Met and DL-Met but not DL-HMTBA supplementation enhanced the neutral amino acid transporters ATB0,+ and B0AT gene expression in various small intestinal segments. All three Met sources increased monocarboxylic acid transporter (MCT1) gene expression in the jejunum. DL-HMTBA and L-Met fed chickens showed greater hepatic L-HMTBA oxidase (HAO1) gene expression. DL-Met increased glutamic-oxaloacetic transaminase 2 (GOT2) gene expression in the duodenum. An in vitro study with tissue explants, however, did not demonstrate a similar gene expression pattern as that in the in vivo study. Lastly, RNA sequencing results illustrated that Met deficiency could lead to many differentially expressed genes but different supplemental Met sources had no influence on hepatic gene expression profiles. In conclusion, as common dietary supplemental Met sources, L-Met, DL-Met and DL-HMTBA exhibited similarity in impacting intestinal amino acid/peptide/monocarboxylic acid transporter gene expression and Met converting enzyme activity. The regulatory roles of Met as an antioxidant and nutrient signaling in cell metabolism were not affected by different dietary supplemental Met sources.
Ph. D.
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17

Goldoni, Luca. "Prime Numbers and Polynomials." Doctoral thesis, University of Trento, 2010. http://eprints-phd.biblio.unitn.it/384/1/Thesis.pdf.

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This thesis deals with the classical problem of prime numbers represented by polynomials. It consists of three parts. In the first part I collected many results about the problem. Some of them are quite recent and this part can be considered as a survey of the state of the art of the subject. In the second part I present two results due to P. Pleasants about the cubic polynomials with integer coefficients in several variables. The aim of this part is to simplify the works of Pleasants and modernize the notation employed. In such a way these important theorems are now in a more readable form. In the third part I present some original results related with some algebraic invariants which are the key-tools in the works of Pleasants. The hidden diophantine nature of these invariants makes them very difficult to study. Anyway some results are proved. These results make the results of Pleasants somewhat more effective.
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18

Ture, Savadkoohi Bita. "Analysis of 3D scanning data for optimal custom footwear manufacture." Doctoral thesis, University of Trento, 2010. http://eprints-phd.biblio.unitn.it/461/1/TureSavadkoohi_Bita.pdf.

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Very few standards exist for tting products to people. Footwear fit is a noteworthy example for consumer consideration when purchasing shoes. As a result, footwear manufacturing industry for achieving commercial success encountered the problem of developing right footwear which is fulfills consumer's requirement better than it's competeries. Mass customization starts with understanding individual customer's requirement and it finishes with fulllment process of satisfying the target customer with near mass production efficiency. Unlike any other consumer product, personalized footwear or the matching of footwear to feet is not easy if delivery of discomfort is predominantly caused by pressure induced by a shoe that has a design unsuitable for that particular shape of foot. Footwear fitter have been using manual measurement for a long time, but the combination of 3D scanning systems with mathematical technique makes possible the development of systems, which can help in the selection of good footwear for a given customer. This thesis, provides new approach for addressing the computerize footwear fit customization in industry problem. The design of new shoes starts with the design of the new shoe last. A shoe last is a wooden or metal model of human foot on which shoes are shaped. Despite the steady increase in accuracy, most available scanning techniques cause some deficiencies in the point cloud and a set of holes in the triangle meshes. Moreover, data resulting from 3D scanning are given in an arbitrary position and orientation in a 3D space. To apply sophisticated modeling operations on these data sets, substantial post-processing is usually required. We described a robust algorithm for filling holes in triangle mesh. First, the advance front mesh technique is used to generate a new triangular mesh to cover the hole. Next, the triangles in initial patch mesh is modified by estimating desirable normals instead of relocating them directly. Finally, the Poisson equation is applied to optimize the new mesh. After obtaining complete 3D model, the result data must be generated and aligned before taking this models for shape analysis such as measuring similarity between foot and shoe last data base for evaluating footwear it. Principle Component Analysis (PCA), aligns a model by considering its center of mass as the coordinate system origin, and its principle axes as the coordinate axes. The purpose of the PCA applied to a 3D model is to make the resulting shape independent to translation and rotation asmuch as possible. In analysis, we applied "weighted" PCA instead of applying the PCA in a classical way (sets of 3D point-clouds) for alignment of 3D models. This approach is based on establishing weights associated to center of gravity of triangles. When all of the models are aligned, an efficient algorithm to cut the model to several sections toward the heel and toe for extracting counters is used. Then the area of each contour is calculated and compared with equal sections in shoe last data base for finding best footwear fit within the shoe last data base.
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19

Dalvit, Ester. "New proposals for the popularization of braid theory." Doctoral thesis, Università degli studi di Trento, 2011. https://hdl.handle.net/11572/368720.

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Braid theory is a very active research field. Braids can be studied from variuos points of view and have applications in different fields, e.g. in mathematical physics and in biology. In this thesis we provide a formal introduction to some topics in the mathematical theory of braids and two possible approaches to this field at a popular level: a movie and a workshop. The scientific movie addressed to a non-specialist audience has been realized using the free ray-tracer POV-Ray. It is divided into four parts, each of which has a length of about 15 minutes. The content ranges from the introduction of basic concepts to deep results. The workshop activity is based on the action of braids on loops and aims to invite and lead the audience to a mathematical formalization of the principal concepts involved: braids, curves and group actions.
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20

Kahlin, Lina. "Resolution 1325 : MOT:s möjlighet att arbeta med genusfrågor?" Thesis, Swedish National Defence College, Swedish National Defence College, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:fhs:diva-70.

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Den här uppsatsens syfte var att, ur ett genusperspektiv, undersöka vilka möjligheter MOT i Afghanistan har för att arbeta mot målet i FN:s resolution 1325. Min fråga var hur arbetet påverkades om teamen bestod av endast män, endast kvinnor respektive både män och kvinnor.

Uppsatsen är indelad i tre delar. I den första delen förklaras centrala begrepp för att ge en förståelse för kommande text. I den andra delen diskuteras hur MOT under FS11 i Afghanistan arbetade med resolutionen och i den tredje delen ges förslag på hur kvinnliga och manliga soldater i ett MOT borde arbeta för att, på bästa sätt, uppnå målet i resolution 1325. Undersökningen är baserad på litteratur, rapporter och intervjuer.

Resultatet av undersökningen visar att både kvinnliga och manliga soldater kunde arbeta enligt resolutionen men med olika resultat. Det var enklare för kvinnliga soldater att nå ut till de lokala kvinnorna samtidigt som de enbart genom sin närvaro gav missionen en kvinnlig infallsvinkel. Manliga soldater hade svårare att skapa lika starka kontakter med de lokala kvinnorna och avsaknaden av kvinnor i teamet gav ett hårdare intryck.

Min slutsats är att MOT innehållande både manliga och kvinnliga soldater är de mest effektiva. Ett blandat team ökar möjligheterna att inhämta och sprida information, visar lokalbefolkningen att män och kvinnor kan arbeta tillsammans och ger chefen möjlighet att lösa uppgifter i ett bredare spektrum. MOT med endast män eller endast kvinnor kan också arbeta enligt resolutionen men uppnår ett sämre resultat.


The purpose of this essay was to examine what chances the MOTs´ in Afghanistan had in working towards the objective in the UN resolution 1325. My question was how the work was affected when the teams consisted of only men, only women and a mix of men and women.

The essay is divided in three parts. The first part explains and defines the concept of the UN resolution 1325. The second part examines the MOTs´ work according to the resolution and the third part suggests how male and female soldiers can work in order to achieve the objective stated in the resolution. The examination is based on literature, reports and interviews.

The result of the examination shows that both male and female soldiers were able to work according to the resolution but with different results. It was easier for female soldiers to reach the local women and the female soldiers´ presence gave the mission a female approach. For male soldiers it was more difficult to establish a contact with the local women and the lack of women in the team made the team seem harsher.

My conclusion is that MOTs´s with both male and female soldiers are the most efficient ones. A mixed team increases the opportunities to gather and spread information, shows the local population that men and women can work together and gives the commander an opportunity to perform his tasks in a wider spectrum.

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21

Kraus, Maria Christina [Verfasser]. "Plaquedifferenzierung mittels MRT zur Prognoseeinschätzung bei Patienten mit Carotisstenose / Maria Christina Kraus." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2013. http://d-nb.info/1035638576/34.

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22

Boegershausen, Kai. "Visualisierung von myokardialem Narbengewebe mittels MRT bei Patienten mit korrigierter Fallot-Tetralogie." Doctoral thesis, Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-192729.

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Die Fallot-Tetralogie ist ein angeborener Herzfehler, der sich aus der Kombination von vier verschiedenen anatomischen Fehlbildungen zusammensetzt. In der Diagnostik kommen bevorzugt die Echokardiografie und die Magnetresonztomografie (MRT) zum Einsatz. Die MRT stellt dabei bei der Erfassung volumetrischer Parameter, insbesondere beim echokardiographisch nicht immer vollständig einsehbaren rechten Ventrikel, den Goldstandard dar. Zudem bietet die MRT die Möglichkeit der Gewebecharakterisierung, inklusive der Darstellung von myokardialer Fibrose. In dieser Studie wurden 67 Patienten nach korrigierter Fallot-Tetralogie mittels MRT untersucht. Dabei lag der Schwerpunkt auf der Visualisierung und Quantifizierung der myokardialen Fibrose mittels Delayed Enhancement-Technik in beiden Ventrikeln. Ziel war es, die Prädilektionsstellen von Delayed Enhancement nach Korrektur einer Fallot-Tetralogie zu beschreiben und seine Beziehung zum Auftreten von ventrikulären Arrhythmien und weiteren kardialen und anamnestischen Parametern zu ermitteln. Es stellte sich heraus, dass Delayed Enhancement bevorzugt im rechten Ventrikel zu finden ist. Es konnte kein Zusammenhang mit dem Auftreten ventrikulärer Arrhythmien, zum Patientenalter während der Korrektur-Operation sowie zu volumetrischen- und Ergometriedaten hergestellt werden. Das Auftreten ventrikulärer Arrhythmien war jedoch signifikant abhängig sowohl vom Patientenalter zum Zeitpunkt der Korrektur-Operation als auch vom Patientenalter zum Zeitpunkt der MRT-Untersuchung.
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23

Stumpp, Patrick. "PET/MRT in der onkologischen Diagnostik mit dem Schwerpunkt Kopf-Hals-Tumoren." Doctoral thesis, Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-214783.

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Erst seit 2010 sind kombinierte Positronenemissionstomographie- Magnetresonanztomographie-Geräte (PET/MRT) zur hybriden Bildgebung verfügbar. Die mit der Entwicklung der Geräte verbundenen Hoffnungen bezüglich der onkologischen Diagnostik lagen zunächst auf einer verbesserten Genauigkeit in der Tumordetektion im Vergleich zur PET/CT. Rasch wurde jedoch deutlich, dass insbesondere die Möglichkeit der non-invasiven, multiparametrischen Charakterisierung von Tumorerkrankungen einen wesentlichen Vorteil der PET/MRT gegenüber der PET/CT darstellt. Der im Universitätsklinikum Leipzig AöR 2011 installierte PET/MRT-Scanner war einer der ersten weltweit und in dieser Habilitationsschrift sind die ersten Erfahrungen mit dieser Methode auf dem Gebiet der onkologischen Diagnostik zusammengefasst. Schwerpunkt ist dabei die Diagnostik von Kopf-Hals-Tumoren, da in diesem Bereich die CT aufgrund des im Vergleich zur MRT schlechteren Weichteilkontrastes Einschränkungen aufweist. In dieser Schrift werden zunächst die unterschiedlichen Konzepte im Gerätedesign der PET/MRT und die Besonderheiten der PET/MRT im Vergleich zur PET/CT erläutert. Auch die kritischen Punkte, die bei der Implementierung eines PET/MRT-Scanners zu beachten sind, werden detailliert dargestellt. Hierbei werden besonders die baulichen und organisatorischen Aspekte berücksichtigt, es werden aber auch Hinweise zur Qualitätskontrolle und zur Entwicklung von Untersuchungsprotokollen gegeben. In der ersten klinischen Studie zur Anwendung der PET/MRT mit 18F-Fluorodesoxyglucose (18F-FDG) bei Patienten mit Kopf-Hals-Tumoren konnten wir hinsichtlich Sensitivität und Spezifität noch keine Unterschiede zur PET/CT nachweisen. Allerdings war hier die untersuchte Patientengruppe heterogen und enthielt sowohl Primär- als auch Rezidivtumore. Aktuell konzentriert sich die onkologische Forschung am PET/MRT auf die Möglichkeiten der multiparametrischen Bildgebung zur Detektion und vor allem Charakterisierung von Tumorerkrankungen. Hier konnten wir signifikante Korrelationen von Glukosestoffwechsel und verschiedenen Perfusionsparametern bei Patienten mit Kopf-Hals-Tumoren nachweisen. Bei Patientinnen mit Zervixkarzinom konnte ein inverser Zusammenhang zwischen Glukosestoffwechsel und Diffusionsrestriktion nachgewiesen werden. Die letzte aufgeführte Arbeit zeigt die Korrelationen zwischen der bildgebenden Tumorcharakterisierung und histopathologischen Ergebnissen bei Kopf-Hals-Tumoren, wo wir Zusammenhänge von Kernfläche und dem Proliferationsmarker Ki-67 mit Diffusionseigenschaften bzw. Glukosestoffwechsel im Tumorgewebe nachweisen konnten.
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24

Laubner, Steffi [Verfasser]. "Zusammenhang zwischen MRT-Befunden und klinischen Symptomen bei Hunden mit Hydrozephalus im Vergleich zu Hunden mit Ventrikulomegalie / Steffi Laubner." Gießen : Universitätsbibliothek, 2016. http://d-nb.info/1090784309/34.

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25

Domínguez, Domínguez Juan Francisco García Hernández Benjamín. "Lexemática latina : estudios de los verbos de "encontrar /." León : Universidad de León, Secretariado de Publicaciones, 1995. http://catalogue.bnf.fr/ark:/12148/cb376842089.

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26

Stelzig, Philipp Emanuel. "On problems in homogenization and two-scale convergence." Doctoral thesis, Università degli studi di Trento, 2012. https://hdl.handle.net/11572/368072.

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This thesis addresses two problems from the theory of periodic homogenization and the related notion of two-scale convergence. Its main focus rests on the derivation of equivalent transmission conditions for the interaction of two adjacent bodies which are connected by a thin layer of interface material being perforated by identically shaped voids. Herein, the voids recur periodically in interface direction and shall in size be of the same order as the interface thickness. Moreover, the constitutive properties of the material occupying the bodies adjacent to the interface are assumed to be described by some convex energy densities of quadratic growth. In contrast, the interface material is supposed to show extremal" constitutive behavior. More precisely
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27

Bottazzi, Emanuele. "Nonstandard Models in Measure Theory and in functional Analysis." Doctoral thesis, Università degli studi di Trento, 2017. https://hdl.handle.net/11572/368322.

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This thesis is concerned with the study of nonstandard models in measure theory and in functional analysis. In measure theory, we define elementary numerosities, that are additive measures that take on values in a non-archimedean field and for which the measure of every singleton is 1. We have shown that, by taking the ratio with a suitable unit of measurement, from a numerosity it can be defined a non-atomic real-valued measure, and that every non-atomic measure can be obtained from a numerosity by this procedure. We then used numerosities to develop a model for the probability of infinite sequences of coin tosses coherent with the original ideas of Laplace. In functional analysis, we introduce a space of functions of nonstandard analysis with a formally finite domain, that extends both the space of distributions and the space of Young measures. Among the applications of this space of functions, we develop a continuous-in-time, discrete-in-space nonstandard formulation for a class of ill-posed forward-backward parabolic equations, and on the study of the regularity and asymptotic behaviour of its nonstandard solutions. This approach proved to be a viable alternative to the study of the vanishing viscosity limit of the solution of a pseudoparabolic regularization of the original problem.
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28

Bonafini, Mauro. "Variational and convex approximations of 1-dimensional optimal networks and hyperbolic obstacle problems." Doctoral thesis, Università degli studi di Trento, 2019. https://hdl.handle.net/11572/369106.

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In this thesis we investigate variational problems involving 1-dimensional sets (e.g., curves, networks) and variational inequalities related to obstacle-type dynamics from a twofold prospective. On one side, we provide variational approximations and convex relaxations of the relevant energies and dynamics, moving mainly within the framework of Gamma-convergence and of convex analysis. On the other side, we thoroughly investigate the numerical optimization of the corresponding approximating energies, both to recover optimal 1-dimensional structures and to accurately simulate the actual dynamics.
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29

Rimoldi, Anna. "On algebraic and statistical properties of AES-like ciphers." Doctoral thesis, Università degli studi di Trento, 2009. https://hdl.handle.net/11572/367817.

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The Advanced Encryption Standard (AES) is nowadays the most widespread block cipher in commercial applications. It represents the state-of-art in block cipher design and provides an unparalleled level of assurance against all known cryptanalytic techniques, except for its reduced versions. Moreover, there is no known efficient way to distinguish it from a set of random permutations. The AES (and other modern block ciphers) presents a highly algebraic structure, which led researchers to exploit it for novel algebraic attacks. These tries have been unsuccessful, except for academic reduced versions. Starting from an intuition by I. Toli, we have developed a mixed algebraic-statistical attack. Using the internal algebraic structure of any AES-like cipher, we build an algebraic setting where a related-key (statistical) distinguishing attack can be mounted. Our data reveals a significant deviation of the full AES-128 from a set of random permutations. Although there are recent successful related-key attacks on the full AES-192 and the full AES-256 (with non-practical complexity), our attack would be the first-ever practical distinguishing attack on the full AES-128 (to the best of our knowledge).
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30

Paterno, Valentina. "Special rationally connected manifolds." Doctoral thesis, Università degli studi di Trento, 2009. https://hdl.handle.net/11572/368764.

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We consider smooth complex projective varieties X which are rationally connected by rational curves of degree d with respect to a fixed ample line bundle L on X, and we focus our attention on conic connected manifolds (d=2) and on rationally cubic connected manifolds (d=3). Conic connected manifolds were studied by Ionescu and Russo; they considered conic connected manifolds embedded in projective space (i.e. L is very ample) and they proved a classification theorem for these manifolds. We show that their classification result holds true assuming just the ampleness of L. Moreover we give a different proof of a theorem due to Kachi and Sato; this result characterizes a special subclass of conic connected manifolds. As already said before, we study also rationally cubic connected manifolds. We prove that if rationally cubic connected manifolds are covered by “lines†, i.e. by curves of degree 1 with respect to L, then the Picard number of X is equal to or less than 3; moreover we show that if the Picard number is equal to 3 then there is a covering family of “lines†whose numerical class spans a negative extremal ray of the Kleiman-Mori cone of X. Unfortunately, for rationally cubic connected manifolds which don't admit a covering family of “lines†there isn't an upper bound on the Picard number. However we prove that if we consider rationally cubic connected manifolds which are not covered by “lines†but are Fano then up to a few exceptions in dimension 2 also the Picard number of these manifolds is equal to or less than 3. In particular, supposing that the dimension of X is greater than 2, we show that either the Picard number is equal to or less than 2 or X is the blow up of projective space along two disjoint subvarieties that are linear subspaces or quadrics.
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31

Ugolini, Simone. "Graded Lie algebras of maximal class in positive characteristic, generated by two elements of different weights." Doctoral thesis, Università degli studi di Trento, 2010. https://hdl.handle.net/11572/369223.

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32

Dalvit, Ester. "New proposals for the popularization of braid theory." Doctoral thesis, University of Trento, 2011. http://eprints-phd.biblio.unitn.it/663/1/dalvit_popularization_braid.pdf.

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Braid theory is a very active research field. Braids can be studied from variuos points of view and have applications in different fields, e.g. in mathematical physics and in biology. In this thesis we provide a formal introduction to some topics in the mathematical theory of braids and two possible approaches to this field at a popular level: a movie and a workshop. The scientific movie addressed to a non-specialist audience has been realized using the free ray-tracer POV-Ray. It is divided into four parts, each of which has a length of about 15 minutes. The content ranges from the introduction of basic concepts to deep results. The workshop activity is based on the action of braids on loops and aims to invite and lead the audience to a mathematical formalization of the principal concepts involved: braids, curves and group actions.
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33

Oriente, Francesco. "Classifying semisimple orbits of theta-groups." Doctoral thesis, Università degli studi di Trento, 2012. https://hdl.handle.net/11572/368303.

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I consider the problem of classifying the semisimple orbits of a theta-group. For this purpose, once a preliminary presentation of the theoretical subjects where my problem arises from, I first give an algorithm to compute a Cartan subspace; subsequently I describe how to compute the little Weyl group.
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34

Marcolla, Chiara. "On structure and decoding of Hermitian codes." Doctoral thesis, Università degli studi di Trento, 2013. https://hdl.handle.net/11572/368401.

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Given a linear code, it is important both to identify fast decoding algorithms and to estimate the rst terms of its weight distribution. Ecient decoding algorithms allow the exploitation of the code in practical situations, while the knowledge of the number of small-weight codewords allows to estimate its decoding performance. For ane-variety codes and its subclass formed by Hermitian codes, both problems are as yet unsolved. We investigate both and provide some solutions for special cases of interest. The rst problem is faced with use of the theory of Gröbner bases for zero-dimensional ideals. The second problem deals in particular with small-weight codewords of high-rate Hermitian codes. We determine them by studying some geometrical properties of the Hermitian curve, specically the intersection number of the curve with lines and parabolas.
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35

Altavilla, Amedeo. "Quaternionic slice regular functions on domains without real points." Doctoral thesis, Università degli studi di Trento, 2014. https://hdl.handle.net/11572/368416.

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In this thesis I've explored the theory of quaternionic slice regular functions. More precisely I've studied some rigidity properties, some differential issues and an application in complex differential geometry. This application concerns the constructions and classifications of orthogonal complex structures on open domains of the four dimensional euclidean space.
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36

Tasin, Luca. "Birational Maps in the Minimal Model Program." Doctoral thesis, Università degli studi di Trento, 2013. https://hdl.handle.net/11572/368878.

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37

Pizzato, Marco. "Some Problems Concerning Polynomials over Finite Fields, or Algebraic Divertissements." Doctoral thesis, Università degli studi di Trento, 2013. https://hdl.handle.net/11572/367913.

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In this thesis we consider some problems concerning polynomials over finite fields. The first topic is the action of some groups on irreducible polynomials. We describe orbits and stabilizers. Next, we consider transformations of irreducible polynomials by quadratic and cubic maps and study the irreducibility of the polynomials obtained. Finally, starting from PN functions and monomials, we generalize this concept, introducing k-PN monomials and classifying them for small values of k and for fields of order p, p^2 and p^4.
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38

Pernigotti, Letizia. "Geometry of moduli spaces of higher spin curves." Doctoral thesis, Università degli studi di Trento, 2013. https://hdl.handle.net/11572/369303.

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ABSTRACT: Roughly speaking, the moduli space of higher spin curves parametrizes equivalence classes of pairs (C, L) where C is a smooth genus g algebraic curve and L is a line bundle on it whose r-th tensor power is isomorphic to the canonical bundle of the curve. The aim of the talk is to discuss important geometrical properties of these spaces under different points of view: one possible compactification together with the description of the rational Picard group, their birational geometry in some low genus cases and their relation with some special locus inside the classical moduli spaces of curves.
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39

Faccin, Paolo. "Computational problems in algebra: units in group rings and subalgebras of real simple Lie algebras." Doctoral thesis, Università degli studi di Trento, 2014. https://hdl.handle.net/11572/368142.

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In the first part of the thesis I produce and implement an algorithm for obtaining generators of the unit group of the integral group ring ZG of finite abelian group G. We use our implementation in MAGMA of this algorithm to compute the unit group of ZG for G of order up to 110. In the second part of the thesis I show how to construct multiplication tables of the semisimple real Lie algebras. Next I give an algorithm, based on the work of Sugiura, to find all Cartan subalgebra of such a Lie algebra. Finally I show algorithms for finding semisimple subalgebras of a given semisimple real Lie algebra.
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40

Scarbolo, Claudio. "Graded Lie algebras of maximal class in characteristic p, generated by two elements of degree 1 and p." Doctoral thesis, Università degli studi di Trento, 2014. https://hdl.handle.net/11572/368969.

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Lie algebras of maximal class (or filiform Lie algebras) are the Lie-theoretic analogue of pro-p-groups of maximal class. In particular, they are 2-generated. If one further assumes that the algebras are graded over the positive integers, then over a field of characteristic p it has been shown that a classification is possible provided one generator has degree 1 and the other has either degree 1 or 2. In this thesis I give a classification of graded Lie algebras of maximal class with generators of degree 1 and p, respectively.
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41

Piva, Matteo. "Algebraic methods for the distance of cyclic codes." Doctoral thesis, Università degli studi di Trento, 2014. https://hdl.handle.net/11572/368507.

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In this thesis we provide known and new results which explain the relationship between the actual minimum distance of cyclic codes, bounds that use only information on the defining sets of cyclic codes to lower bound the distance (root bounds) and bounds that also need the knowledge of the defining sets of all cyclic subcodes (border bounds). We propose a new bound which is provably better of many known bounds and that can be computed in polynomial time with respect to the length of the code. We sketch how to use the generalized Newton identities to give alternative proofs of known bounds. Finally, we use Groebner bases to prove that the optimal root bound can be computed in finite time.
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42

Platoni, Irene. "Complete Arcs and Caps in Galois Spaces." Doctoral thesis, Università degli studi di Trento, 2014. https://hdl.handle.net/11572/368555.

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Galois spaces, that is affine and projective spaces of dimension N ≥ 2 defined over a finite (Galois) field F_q, are well known to be rich of nice geometric, combinatorial and group theoretic properties that have also found wide and relevant applications in several branches of Combinatorics, as well as in more practical areas, notably Coding Theory and Cryptography. The systematic study of Galois spaces was initiated in the late 1950’s by the pioneering work of B. Segre [59]. The trilogy [34, 36, 42] covers the general theory of Galois spaces including the study of objects which are linked to linear codes. Typical such objects are plane arcs and their generalizations - especially caps and arcs in higher dimensions - whose code theoretic counterparts are distinguished types of error-correcting and covering linear codes. Their investigation has received a great stimulus from Coding Theory, especially in the last decades; see the survey papers [40, 41]. An important issue in this context is to ask for explicit constructions of small complete arcs and small complete caps. A cap in a Galois space is a set of points no three of which are collinear. A cap is complete if its secants (lines through two points of the set) cover the whole space. An arc in a Galois space of dimension N is a set of points no N+1 of which lying on the same hyperplane. In analogy with caps, an arc which is maximal with respect to set-theoretical inclusion is said to be complete. Also, arcs coincide with caps in Galois planes. From these geometrical objects, there arise linear codes which turn out to have very good covering properties, provided that the size of the set is small with respect to the dimension N and the order q of the ambient space. For the size t(AG(N,q)) of the smallest complete caps in a Galois affine space AG(N,q) of dimension N over F_q, the trivial lower bound is √2q^{N−1/2}. General constructions of complete caps whose size is close to this lower bound are only known for q even and N odd, see [16, 19, 29, 52]. When N is even, complete caps of size of the same order of magnitude as cq^{N/2}, with c a constant independent of q, are known to exist for both the odd and the even order case, see [16, 18, 28, 29, 31] (see also Section 2.2 and the references therein). Whereas, few constructions of small complete arcs in Galois spaces of dimension N>2 are known. In [65, 66, 67], small complete arcs having many points in common with the normal rational curve are investigated (see Section 4.2.3 for comparisons with our results). In this thesis, new infinite families of complete arcs and caps in higher dimensional spaces are constructed from algebraic curves defined over a finite field. In most cases, no smallest complete caps/arcs were previously known in the literature. Although caps and arcs are rather combinatorial objects, constructions and proofs sometimes heavily rely on concepts and results from Algebraic Geometry in positive characteristic.
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43

Tinnirello, Claudia. "Cyclic Codes: Low-Weight Codewords and Locators." Doctoral thesis, Università degli studi di Trento, 2016. https://hdl.handle.net/11572/369123.

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Error correcting codes has become an integral part of the design of reliable data transmissions and storage systems. They are also playing an increasingly important role for other applications such as the analysis of pseudorandom sequences and the design of secure cryptosystems. Cyclic codes form a large class of widely used error correcting codes, including important codes such as the Bose-Chaudhuri-Hocquenghem (BCH) codes, quadratic residue (QR) codes and Golay codes. In this thesis I tackle two problems related to cyclic codes: finding low-weight codewords and decoding. Computing efficiently low-weight codewords of a cyclic code is often a key ingredient of correlation attacks to LFSR-based stream ciphers. The best general purpose algorithm is based on the generalized birthday problem. In the first part of the thesis I show an alternative approach based on discrete logarithms which has - in some cases relevant for applications - much lower memory complexity requirements and a comparable time complexity. The second part of the thesis is devoted to some results concerning efficient bounded-distance decoding for cyclic codes.
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44

Meneghetti, Alessio. "Optimal Codes and Entropy Extractors." Doctoral thesis, Università degli studi di Trento, 2017. https://hdl.handle.net/11572/368164.

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In this work we deal with both Coding Theory and Entropy Extraction for Random Number Generators to be used for cryptographic purposes. We start from a thorough analysis of known bounds on code parameters and a study of the properties of Hadamard codes. We find of particular interest the Griesmer bound, which is a strong result known to be true only for linear codes. We try to extend it to all codes, and we can determine many parameters for which the Griesmer bound is true also for nonlinear codes. In case of systematic codes, a class of codes including linear codes, we can derive stronger results on the relationship between the Griesmer bound and optimal codes. We also construct a family of optimal binary systematic codes contradicting the Griesmer bound. Finally, we obtain new bounds on the size of optimal codes. Regarding the study of random number generation, we analyse linear extractors and their connection with linear codes. The main result on this topic is a link between code parameters and the entropy rate obtained by a processed random number generator. More precisely, to any linear extractor we can associate the generator matrix of a linear code. Then, we link the total variation distance between the uniform distribution and the probability mass function of a random number generator with the weight distribution of the linear code associated to the linear extractor. Finally, we present a collection of results derived while pursuing a way to classify optimal codes, such as a probabilistic algorithm to compute the weight distribution of linear codes and a new bound on the size of codes.
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45

Cancian, Nicola. "On Semi-isogenous Mixed Surfaces." Doctoral thesis, Università degli studi di Trento, 2017. https://hdl.handle.net/11572/369295.

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Let C be a compact Riemann surface. Let us consider a finite group acting on CxC, having some elements that exchange the factors, and assume that the subgroup of those elements that do not exchange the factors acts freely. We call the quotient a Semi-isogenous Mixed Surface. In this work we investigate these surfaces and we explain how their geometry is encoded in the group. Based on this, we present an algorithm to classify the Semi-isogenous Mixed Surfaces with given geometric genus, irregularity and self-intersection of the canonical class. In particular we give the classification of Semi-isogenous Mixed Surfaces with K^2>0 and holomorphic Euler-Poincaré characteristic equal to 1, where new examples of minimal surfaces of general type appear. Minimality of Semi-isogenous Mixed Surfaces is discussed using two different approaches. The first one involves the study of the bicanonical system of such surfaces: we prove that we can relate the dimension of its first cohomology group to the rank of a linear map that involves only curves. The second approach exploits Hodge index theorem to bound the number of exceptional curves that live on a Semi-isogenous Mixed Surface.
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46

Civino, Roberto. "Differential attacks using alternative operations and block cipher design." Doctoral thesis, Università degli studi di Trento, 2018. https://hdl.handle.net/11572/368586.

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Block ciphers and their security are the main subjects of this work. In the first part it is described the impact of differential cryptanalysis, a powerful statistical attack against block ciphers, when operations different from the one used to perform the key addition are considered on the message space. It is proven that when an alternative difference operation is carefully designed, a cipher that is proved secure against classical differential cryptanalysis can instead be attacked using this alternative difference. In the second part it is presented a new design approach of round functions for block ciphers. The proposed round functions can give to the cipher a potentially better level of resistance against statistical attacks. It is also shown that the corresponding ciphers can be proven secure against a well-known algebraic attack, based on the action of the permutation group generated by the round functions of the cipher.
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47

Longo, Riccardo. "Formal Proofs of Security for Privacy-Preserving Blockchains and other Cryptographic Protocols." Doctoral thesis, Università degli studi di Trento, 2018. https://hdl.handle.net/11572/368971.

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Cryptography is used to protect data and communications. The basic tools are cryptographic primitives, whose security and efficiency are widely studied. But in real-life applications these primitives are not used individually, but combined inside complex protocols. The aim of this thesis is to analyse various cryptographic protocols and assess their security in a formal way. In chapter 1 the concept of formal proofs of security is introduced and the main categorisation of attack scenarios and types of adversary are presented, and the protocols analysed in the thesis are briefly introduced with some motivation. In chapter 2 are presented the security assumptions used in the proofs of the following chapters, distinguishing between the hardness of algebraic problems and the strength of cryptographic primitives. Once that the bases are given, the first protocols are analysed in chapter 3, where two Attribute Based Encryption schemes are proven secure. First context and motivation are introduced, presenting settings of cloud encryption, alongside the tools used to build ABE schemes. Then the first scheme, that introduces multiple authorities in order to improve privacy, is explained in detail and proven secure. Finally the second scheme is presented as a variation of the first one, with the aim of improving the efficiency performing a round of collaboration between the authorities. The next protocol analysed is a tokenization algorithm for the protection of credit cards. In chapter 4 the advantages of tokenization and the regulations required by the banking industry are presented, and a practical algorithm is proposed, and proven secure and compliant with the standard. In chapter 5 the focus is on the BIX Protocol, that builds a chain of certificates in order to decentralize the role of certificate authorities. First the protocol and the structure of the certificates are introduced, then two attack scenarios are presented and the protocol is proven secure in these settings. Finally a viable attack vector is analysed, and a mitigation approach is discussed. In chapter 6 is presented an original approach on building a public ledger with end-to-end encryption and a one-time-access property, that make it suitable to store sensitive data. Its security is studied in a variety of attack scenarios, giving proofs based on standard algebraic assumptions. The last protocol presented in chapter 7 uses a proof-of-stake system to maintain the consistency of subchains built on top of the Bitcoin blockchain, using only standard Bitcoin transactions. Particular emphasis is given to the analysis of the refund policies employed, proving that the naive approach is always ineffective whereas the chosen policy discourages attackers whose stake falls below a threshold, that may be adjusted varying the protocol parameters.
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48

Bonini, Matteo. "Intersections of Algebraic Curves and their link to the weight enumerators of Algebraic-Geometric Codes." Doctoral thesis, Università degli studi di Trento, 2019. https://hdl.handle.net/11572/368573.

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Channel coding is the branch of Information Theory which studies the noise that can occur in data transmitted through a channel. Algebraic Coding Theory is the part of Channel Coding which studies the possibility to detect and correct errors using algebraic and geometric techniques. Nowadays, the best performing linear codes are known to be mostly algebraic geometry codes, also named Goppa codes, which arise from an algebraic curve over a finite field, by the pioneering construction due to V. D. Goppa. The best choices for curves on which Goppa's construction and its variants may provide codes with good parameters are those with many rational points, especially maximal curves attaining the Hasse-Weil upper bound for the number of rational points compared with the genus of the curve. Unfortunately, maximal curves are difficult to find. The best known examples of maximal curves are the Hermitian curve, the Ree curve, the Suzuki curve, the GK curve and the GGS curve. In the present thesis, we construct and investigate algebraic geometry codes (shortly AG codes), their parameters and automorphism groups.
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49

Rapa, Alessandro. "Simple objects in the heart of a t-structure." Doctoral thesis, Università degli studi di Trento, 2019. https://hdl.handle.net/11572/369193.

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Historically, the study of modules over finite dimensional algebras has started with the study of the ones with finite dimension. This is sufficient when dealing with a finite dimensional algebra of finite representation type, where there are only finitely many indecomposable modules of finite length. Indecomposable modules of infinite length occur when dealing with algebras of infinite representation type and the study of pure-injective modules over a finite dimensional algebra is crucial for the problem of describing infinite dimensional modules. In this talk, we consider a specific class of finite dimensional algebras of infinite representation type, called "tubular algebras". Pure-injective modules over tubular algebra have been partially classified by Angeleri Hügel and Kussin, in 2016, and we want to give a contribution to the classification of the ones of "irrational slope". In this talk, first, via a derived equivalence, we move to a more geometrical framework, ie. we work in the category of quasi-coherent sheaves over a tubular curve, and we approach our classification problem from the point of view of tilting/cotilting theory. More precisely, we consider specific torsion pairs cogenerated by infinite dimensional cotilting sheaves and we study the Happel-Reiten-Smalø heart of the corresponding t-structure in the derived category. These hearts are locally coherent Grothendieck categories and, in these categories, the pure-injective sheaves over the tubular curve become injective objects. In order to study injective objects in a Grothendieck category is fundamental the classification of the simple objects. In the seminar, we use some techniques coming from continued fractions and universal extensions to provide a method to construct an infinite dimensional sheaf of a prescribed irrational slope that becomes simple in the Grothendieck category given as the heart of a precise t-structure.
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50

Fabiano, Bonometti. "Gluing silting objects along recollements of well generated triangulated categories." Doctoral thesis, Università degli studi di Trento, 2019. https://hdl.handle.net/11572/367806.

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We provide an explicit procedure to glue (not necessarily compact) silting objects along recollements of triangulated categories with coproducts having a ‘nice’ set of generators, namely, well generated triangulated categories. This procedure is compatible with gluing co-t-structures and it generalizes a result by Liu, Vitória and Yang. We provide conditions for our procedure to restrict to tilting objects and to silting and tilting modules. As applications, we retrieve the classification of silting modules over the Kronecker algebra and the classification of non-compact tilting sheaves over a weighted noncommutative regular projective curve of genus 0.
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