Academic literature on the topic 'Subnormal subgroups'

It is known that a TI-subgroup of a finite group may not be a subnormal subgroup and a subnormal subgroup of a finite group may also not be a TI-subgroup. For the non-abelian subgroups, we prove that if every non-abelian subgroup of a finite group [Formula: see text] is a TI-subgroup or a subnormal subgroup, then every non-abelian subgroup of [Formula: see text] must be subnormal in [Formula: see text]. We also show that the non-cyclic subgroups have the same property.

A group G is said to have the subnormal join property (s.j.p.) if the join of two (and hence of finitely many) subnormal subgroups of G is always subnormal in G. Following Robinson [6], we shall denote the class of groups having this property by . A particular subclass of is , consisting of those groups G in which the join of two subnormals is again subnormal in G and has defect bounded in terms of the defects of the constituent subgroups (for a more precise definition see Section 7 of [6]).In [16], Wielandt showed that groups which satisfy the maximal condition for subnormal subgroups have the s.j.p. Many further results on groups with the s.j.p. were proved in [6] and [7]. In Sections 2 and 3 of this paper, it will be shown that several of these results can be exhibited as corollaries of a few rather more general theorems on the classes , .

The main focus in this work is to establish that L-group theory, which uses the language of functions instead of formal set theoretic language, is capable of capturing most of the refined ideas and concepts of classical group theory. We demonstrate this by extending the notion of subnormality to the L-setting and investigating its properties. We develop a mechanism to tackle the join problem of subnormal L-subgroups. The conjugate L-subgroup as is defined in our previous paper [4] has been used to formulate the concept of normal closure and normal closure series of an L-subgroup which, in turn, is used to define subnormal L-subgroups. Further, the concept of subnormal series has been introduced in L-setting and utilized to establish the subnor-mality of L-subgroups. Also, several results pertaining to the notion of subnormality have been established. Lastly, the level subset characterization of a subnormal L-subgroup is provided after developing a necessary mechanism. Finally, we establish that every subgroup of a nilpotent L-group is subnormal. In fact, it has been exhibited through this work that L-group theory presents a modernized approach to study classical group theory.

AbstractA group G is called normally (subnormally) detectable if the only normal (subnormal) subgroups in any direct product G1 × … × Gn of copies of G are just the direct factors Gi. We give an internal characterization of finite subnormally detectable groups and obtain analogous results for associative rings and for Lie algebras. The main part of the paper deals with a study of normally detectable groups, where we verify a conjecture of T. O. Hawkes in a number of special cases.

AbstractWe consider the class of solvable groups in which all subnormal subgroups have subnormal normalizers, a class containing many well-known classes of solvable groups. Groups of this class have Fitting length three at most; some other information connected with the Fitting series is given.

AbstractA group is called a T-group if all its subnormal subgroups are normal. It is proved here that if G is a periodic (generalized) soluble group in which all subnormal subgroups of infinite rank are normal, then either G is a T-group or it has finite rank. It follows that if G is an arbitrary group whose Fitting subgroup has infinite rank, then G has the property T if and only if all its subnormal subgroups of infinite rank are normal.

It is shown that a hypercentral group that has all subgroups subnormal and every non-nilpotent subgroup of bounded defect is nilpotent. As a consequence, a hypercentral group of length at most ω in which every subgroup is subnormal is nilpotent.

Our aim in this paper is to investigate the restrictions placed on the structure of a finite group if it can be generated by subnormal T-subgroups (a T-group is a group in which every subnormal subgroup is normal). For notational convenience we denote by the class of finite groups that can be generated by subnormal T-subgroups and by the subclass of of those finite groups generated by normal T-subgroups; and for the remainder of this paper we will only consider finite groups.

AbstractWe investigate a finite groupGwith{\mathfrak{F}}-subnormal Sylow subgroups, where{\mathfrak{F}}is a subgroup-closed formation and{\mathfrak{A}_{1}\mathfrak{A}\subseteq\mathfrak{F}\subseteq\mathfrak{N}% \mathcal{A}}. We prove thatGis soluble and the derived subgroup of each metanilpotent subgroup is nilpotent. We also describe the structure of groups in which every Sylow subgroup is{\mathfrak{F}}-subnormal or{\mathfrak{F}}-abnormal.

The Wielandt subgroup, the intersection of normalizers of subnormal subgroups, is non-trivial in any finite group and thus gives rise to a series whose length is a measure of the complexity of a group's subnormal structure. Another measure, akin to the nilpotency class of nilpotent groups, arises from the strong Wielandt subgroup, the intersection of centralizers of nilpotent subnormal sections. This thesis begins an investigation into how these two invariants relate in finite soluble groups. ¶ Complete results are obtained for metabelian groups of odd order: the strong Wielandt length of such a group is at most one more than its Wielandt length, and this bound is best possible. Some progress is made in the wider class of groups with p-length 1 for all primes p. A conjecture for all finite soluble groups, which may be regarded as a subnormal analogue of the embedding of the Kern, is also considered.

Thesis (MSc) -- Stellenbosch University, 2004.
ENGLISH ABSTRACT: In this thesis we give a survey of research done on a problem on subnormal subgroups in factorized groups G = AB, where A and B are two subgroups of G with H a subgroup of A n B which is subnormal in both A and B. It is of interest to know whether or not such a subgroup H will also be subnormal in G. During the past twenty five to thirty years some positive results were obtained in the case where G is a finite group. This was mainly due to work done by Maier and Wielandt, with results by Sidki and Casolo following shortly afterwards. Counterexamples in the case of infinite groups seemed to be extremely hard to construct. For the infinite group case, some positive results were obtained through contributions by amongst others Stonehewer, Franciosi, de Giovanni and Sysak. Most recently some alternative proofs were given by Fransman.
AFRIKAANSE OPSOMMING: In hierdie tesis poog ons om 'n oorsig te gee van navorsing uitgevoer oor 'n probleem rakende subnormale ondergroepe van 'n groep G = AB wat uitgedruk kan word as 'n produk van twee ondergroepe A en B. Daar word gepoog om te bepaal vir watter klasse van groepe dit volg dat as die ondergroep H van A se deursnede met B subnormaal is in beide A en B, sal dit impliseer dat H ook subnormaal in die groep G sal wees. Gedurende die afgelope vyf-en-twintig na dertig jaar is positiewe resultate bewys VIr eindige sodanige groepe deur veralouteurs soos Maier en Wielandt, gevolg deur Sidki en Casolo. Dit blyk dat dit nie maklik is om teenvoorbeelde te vind vir die oneindige geval nie. Daar is wel positiewe resultate gelewer vanweë bydraes deur onder andere Stonehewer, Franciosi, de Giovanni en Sysak. Meer onlangs is ook alternatiewe bewyse gegee deur Fransman.

The purpose of this thesis is to investigate some problems concerning products of groups, that is given a group G with subgroups H and K. We investigate what effect the structures of H and K have on the the structure of the product HK. In chapters 2 and 3 we consider the case where the product is itself a group and in chapter 4 we consider the case where the product need not be a group.

[EN] The scope of this thesis is the abstract finite group theory. All the groups we will consider will be finite. hence, the word "group" will be understood as a synonimous of "finite group". We say that a subgroup H of a group G is solitary when no other subgroup of G is isomorphic to H. A normal subgroup H of a group G is said to be normal solitary when no other normal subgroup of G is isomorphic to H. A normal subgroup N of a group G is said to be quotient solitary when no other normal subgroup K of G gives a quotient isomorphic to G/N. Solitary subgroups, normal solitary subgroups, and quotient solitary subgroups have been recently studied by authors like Thévenaz, who named the solitary subgroups as strongly characteristic subgroups, Kaplan and Levy, Tarnauceanu, and Atanasov and Foguel. The aim of this PhD thesis project is to deepen into the analysis of these subgroup embedding properties, by refining the knowledge of their lattice properties, by obtaining general properties related to classes of groups, and by analysing groups in which the members of some distinguished families of subgroups satisfy these embedding properties. The basic results of group theory that will be used in the memoir appear in Chapter 1. Among them, we comment on some results about soluble groups, supersoluble groups, nilpotent groups, classes of groups, and p-soluble and p-nilpotent groups for a prime p. In Chapter 2, we present the basic concepts about these embedding properties, as well as some basic results satisfied by them. Chapter 3 is devoted to the study of lattice properties of these types of subgroups. In this chapter we deepen into the study of the lattices of solitary subgroups and quotient solitary subgroups developed by Kaplan and Levy and by Tarnauceanu and we check that, even though these lattices consist of normal subgroups, they are not sublattices of the lattice of normal subgroups. We also check that the set of all normal solitary subgroups does not constitute a lattice, which motivates the introduction of the concept of subnormal solitary subgroup as a more suitable tool to deal with lattice properties. In Chapter 4, we study in depth the relations between these embedding properties and classes of groups. We observe that the subnormal solitary subgroups behave well with respect to radicals for Fitting classes and that the residuals for formations are quotient solitary subgroups. We also study conditions under which the radicals with respect to Fitting classes are quotient solitary subgroups and the residuals with respect to formations are solitary subgroups. To finish, we state the natural question of whether the solitary or subnormal solitary subgroups can be regarded as radicals for suitable Fitting classes or whether the quotient solitary subgroups are residuals for suitable Fitting classes. We give a negative answer to this question. Chapter 5 is devoted to the study of groups whose minimal subgroups are solitary, that is, groups with a unique subgroup of order p for each prime p dividing its order. We give a complete classification of these groups and we make some remarks about related problems. Our contributions to this research line have been accepted for their publication in two papers in Communications in Algebra and in Journal of Algebra and its Applications.
[ES] El ámbito de esta tesis es el de la teoría abstracta de grupos finitos. Todos los grupos que consideremos serán finitos. Por ello, la palabra «grupo» se entenderá como sinónima de «grupo finito». Decimos que un subgrupo H de un grupo G es solitario cuando ningún otro subgrupo de G es isomorfo a H. Un subgrupo normal H de un grupo G se dice normal solitario cuando ningún otro subgrupo normal de G es isomorfo a H. Un subgrupo normal N de un grupo G se dice que es solitario para cocientes cuando ningún otro subgrupo normal K de G da un cociente isomorfo a G/N. Los subgrupos solitarios, los subgrupos normales solitarios y los subgrupos solitarios para cocientes han sido recientemente estudiados por autores como Thévenaz, quien bautizó los subgrupos solitarios como subgrupos fuertemente característicos, Kaplan y Levy, Tarnauceanu y Atanasov y Foguel. El objeto de este proyecto de tesis doctoral es el de profundizar en el análisis de estas propiedades de inmersión de subgrupos, afinando en el conocimiento de sus propiedades reticulares, obteniendo propiedades generales en relación con clases de grupos y analizando grupos en los que los miembros de algunas familias destacadas de subgrupos satisfacen estas propiedades de inmersión. Los resultados básicos de teoría de grupos que se utilizan en la memoria aparecen en el capítulo 1. Entre ellos, comentamos algunos resultados sobre grupos resolubles, superresolubles, nilpotentes, clases de grupos y grupos p-resolubles y p-nilpotentes para un primo p. En el capítulo 2 presentamos los conceptos básicos sobre estas propiedades de inmersión, así como algunos resultados básicos que satisfacen. El capítulo 3 está dedicado al estudio de propiedades reticulares de estos tipos de subgrupos. En este capítulo se profundiza en el estudio de los retículos de subgrupos solitarios y solitarios para cocientes llevado a cabo por Kaplan y Levy y por Tarnauceanu y se comprueba que, a pesar de que estos retículos constan de subgrupos normales, no son subretículos del retículo de subgrupos normales. También comprobamos que el conjunto de subgrupos normales solitarios no constituye un retículo, lo que motiva la introducción del concepto de subgrupo subnormal solitario como herramienta más adecuada para tratar propiedades reticulares. En el capítulo 4 estudiamos con profundidad las relaciones entre estas propiedades de inmersión y clases de grupos. Observamos que los subgrupos subnormales solitarios se comportan bien respecto de radicales de clases de Fitting y que los residuales para formaciones son subgrupos solitarios para cocientes. Esto permite mejorar algunos resultados sobre subgrupos solitarios para cocientes. También estudiamos condiciones en que los radicales respecto de clases de Fitting son subgrupos solitarios para cocientes y los residuales respecto de formaciones son subgrupos solitarios. Por último, nos planteamos la cuestión natural de si los subgrupos solitarios o subnormales solitarios pueden verse como radicales para clases de Fitting adecuadas o si los subgrupos solitarios para cocientes son residuales para clases de Fitting adecuadas. Damos una respuesta negativa a esta cuestión. El capítulo 5 está dedicado al estudio de grupos cuyos subgrupos minimales son solitarios, es decir, grupos con un único subgrupo de orden p para cada primo p divisor de su orden. Damos una clasificación completa de estos grupos y hacemos algunas observaciones sobre problemas relacionados. Nuestras aportaciones a esta línea de investigación han sido aceptadas para su publicación en dos artículos en Communications in Algebra y en Journal of Algebra and its Applications.
[CAT] L'àmbit d'aquesta tesi és el de la teoria abstracta de grups finits. Tots els grups que hi considerem seran finits. Per això, la paraula «grup» s'entendrà com a sinònima de «grup finit». Direm que un subgrup H d'un grup G és solitari quan cap altre subgrup de G no és isomorf a H. Un subgrup normal H d'un grup G es diu normal solitari quan cap altre subgrup normal de G no és isomorf a H. Un subgrup normal N d'un grup G es diu que és solitari per a quocients quan cap altre subgrup normal K de G no dóna un quocient isomorf a G/N. Els subgrups solitaris, els subgrups solitaris normals i els subgrups solitaris per a quocients han sigut recentment estudiats per autors com Thévenaz, qui batejà els subgrups solitaris com a subgrups fortament característics, Kaplan i Levy, Tarnauceanu i Atanasov i Foguel. L'objecte d'aquest projecte de tesi doctoral és el d'aprofundir en l'anàlisi d'aquestes propietats d'immersió de subgrups, afinant en el coneixement de les seues propietats reticulars, obtenint propietats generals en relació amb classes de grups i analitzant grups en què els membres d'algunes famílies destacades de subgrups satisfan aquestes propietats d'immersió. Els resultats bàsics de teoria de grups que es fan servir en la memòria apareixen al capítol 1. Entre ells, comentem alguns resultats sobre grups resolubles, superresolubles, nilpotents, classes de grups i grups p-resolubles i p-nilpotents per a un primer p. Al capítol 2 presentem els conceptes bàsics sobre aquestes propietats d'immersió, així com alguns resultats bàsics que satisfan. El capítol 3 està dedicat a l'estudi de propietats reticulars d'aquests tipus de subgrups. En aquest capítol s'aprofundeix en l'estudi dels reticles de subgrups solitaris i solitaris per a quocients dut a terme per Kaplan i Levy i per Tarnauceanu i es comprova que, encara que aquests subgrups consten de subgrups normals, no són subreticles del reticle de subgrups normals. També comprovem que el conjunt de subgrups normals solitaris no constitueix un reticle, la qual cosa motiva la introducció del concepte de subgrup subnormal solitari com a eina més adient per tractar propietats reticulars. Al capítol 4 estudiem amb profunditat les relacions entre aquestes propietats d'immersió i classes de grups. Observem que els subgrups subnormals solitaris es comporten bé respecte de radicals de classes de Fitting i que els residuals per a formacions són subgrups solitaris per a quocients. Açò permet millorar alguns resultats sobre subgrups solitaris per a quocients. També estudien condicions en què els radicals respecte de classes de Fitting són subgrups solitaris per a quocients i els residuals respecte de formacions són subgrups solitaris. Per acabar, ens plantegem la qüestió natural de si els subgrups solitaris o subnormals solitaris poden veure's com a radicals per a classes de Fitting adients o si els subgrups solitaris per a quocients són residuals per a classes de Fitting adients. Donem una resposta negativa a aquesta qüestió. El capítol 5 està dedicat a l'estudi de grups els subgrups minimals dels quals són solitaris, és a dir, grups amb un únic subgrup d'ordre p per a cada primer p divisor del seu ordre. Donem una classificació completa d'aquests grups i fem algunes observacions sobre problemes relacionats. Les nostres aportacions a aquesta línia de recerca han sigut acceptades per a llur publicació a dos articles a Communications in Algebra i a Journal of Algebra and its Applications.
Liriano Castro, ODCDJ. (2015). Subgrupos solitarios de grupos finitos [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/59397
TESIS

The Wielandt subgroup, the intersection of normalizers of subnormal subgroups, is non-trivial in any finite group and thus gives rise to a series whose length is a measure of the complexity of a group's subnormal structure. Another measure, akin to the nilpotency class of nilpotent groups, arises from the strong Wielandt subgroup, the intersection of centralizers of nilpotent subnormal sections. This thesis begins an investigation into how these two invariants relate in finite soluble groups. ¶ Complete results are obtained for metabelian groups of odd order: the strong Wielandt length of such a group is at most one more than its Wielandt length, and this bound is best possible. Some progress is made in the wider class of groups with p-length 1 for all primes p. A conjecture for all finite soluble groups, which may be regarded as a subnormal analogue of the embedding of the Kern, is also considered.

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2007.
Source: Dissertation Abstracts International, Volume: 69-02, Section: B, page: 1041. Adviser: Paul Schupp. Includes bibliographical references (leaf 35) Available on microfilm from Pro Quest Information and Learning.

Several serine protease inhibitorsof plasma inhibit the activated coagulation enzymes but only antithrombin III(AT-III)and heparin cofactor II (HC-II) are implicated in the pathogenesisof the familial thrombosis. Since thefirst publication (1965) many thrombophilic families with reduced AT-III synthesis have been investigated. These studies have proved that the disorder is associated with a high risk forvenous thrombosis and the inheritanceis autosomal dominant. The AT-III activity in the plasma of the affected patients is about 50% of the normalvalue.In recent years the heterogeneity of the inherited AT-III deficiency has been verified. The various AT-III abnormalities are not mere interestingrarities but they provide naturally occurring models for the solution of theoretical problems such as the function of AT-III molecule, the physiological significance of heparin, etc. Furthermore, the clinical manifestationof the particular variants greatly differs from symptomless abnormality tosevere thrombotic cases.In the majority of cases, reduced functional activity is accompanied with a parallel decrease of antigen concentration of AT-III. This is the characteristic feature of the quantitative or Type I ("classical")AT-III deficiency. By means of crossed immunoelectrophoresis, electro-focussing and recombinant DNA techniques the heterogeneity of this group has been established. In one subgroup (Type la) AT-III molecules are normal as regards their biochemical characteristics. In Type lb, subnormal AT-IIIquantity is accompanied with decreased heparin affinity. Differentiation of these subgroups has practical consequences: therapeutic concentrations of heparin apparently does not decrease AT-III level in the plasma of patients with Type lb AT-III deficiency.The other main form is the qualitative deficiency of AT-III (Type II) which is characterised by reduced functional activity at normal antigen concentration. In general, two populations of AT-III molecules can be detected in the blood of these patients: a normal and an abnormal one. Up till now at least 24 different abnormalities were found and designatedwith toponymes. These disorders can be classified with relatively simple laboratory methods such as functional anti-IIaXaFirstDepartment of Medicine, Postgraduate Medical University, Budapest, Hungary.arin cofactor activity, crossed immunoelectrophoresiswith and without heparin, heparin-affinity chromatography. Type na is characterised by profound structural changes of the molecule,variably: reflected in reduced inactivation of F Ha and F Xa, abnormal heparin-AT-III reaction and aberrant immunochemical structure Seven different abnormalities fall into this group (Budapest I, Tokyo, MalmÖ, Chicago, Milano, Trento and Northwick Park). The last three abnormalities are very similar.In Type lib an isolated defect of protease inactivation can be detected and an isolated disturbance of the active centre ofthe molecule is assumed.Until now 6 apparently different variants belonging to this group have been described. (Aalborg, Vicenza, Denver, Hvidovre, Charleville, Milano 2.) Type lie abnormality is characterised by an isolated defect of the heparin-AT-III reaction. In these cases a disturbance of the heparin binding site(s) is assumed. Eleven families with this type of abnormality have been recorded (Ann Arbor, Basel, Paris 1 and 2, Toyama* Tours, Padova I and 2, Algers, Fontainebleu and Budapest 2). This subgroup is heterogeneous in respect ofheparin affinity: in the majority of cases the abnormal AT-III molecules have no heparin affinity at all while in rare cases (such as Basel, Budapest 2) they have reduced affinity.TheType lie AT-III deficiency has several distinctive features compared with the other subtypesJClinically, the thromboembolic complications are rare: in 4 families thrombosis has notoccurred at all. Only one member in each of 4 other families had thrombosis. In 3 families homozygous patients suffered severe thrombosis in young age and/or in unusual localisations (intraarterial, intracardiac, etc.) butthe other heterozygous members were free of thrombotic symptoms. No increased intravascular coagulation could be detected in Type lie heterozygous cases incontrast to the "classical" AT-III deficiency.These observations suggest a different mechanism and clinical manifestation of the deficiency of progressiveserine protease inactivation and of heparin cofactor activity. In case of progressive inactivation, reduction of 50% of the activity predisposes mainly to venous thrombosis as a consequence of the hypercoagulability of theblood. The isolated reduction of heparin cofactor activity seems to bringabout thrombosis in any part of the vascular system, but only if this reduction is as severe as that of the coagulant factors in case of coagulopathies.In accordance with this finding, rare cases of HCII deficiency give rise to thrombosis in both the arteries and the veins. Heparin cofactor activities may play an important role in the antithrombotic mechanism along theendothelial surface of the whole vascular system.