Full Frobenius Groups of Finite Morley Rank and the Feit-Thompson Theorem

2001 ◽  
Vol 7 (3) ◽  
pp. 315-328 ◽  
Author(s):  
Eric Jaligot
Keyword(s):  
Frobenius Group ◽  
Major Obstacle ◽  
Simple Groups ◽  
Morley Rank ◽  
Frobenius Groups ◽  
Finite Morley Rank

AbstractWe show how the notion of full Frobenius group of finite Morley rank generalizes that of bad group, and how it seems to be more appropriate when we consider the possible existence (still unknown) of nonalgebraic simple groups of finite Morley rank of a certain type, notably with no involution. We also show how these groups appear as a major obstacle in the analysis of FT-groups, if one tries to extend the Feit-Thompson theorem to groups of finite Morley rank.

scholarly journals Tame minimal simple groups of finite Morley rank

2004 ◽  
Vol 276 (1) ◽  
pp. 13-79 ◽  
Author(s):  
Gregory Cherlin ◽  
Eric Jaligot
Keyword(s):  
Simple Groups ◽  
Morley Rank ◽  
Finite Morley Rank

On solvable centerless groups of Morley rank 3

1993 ◽  
Vol 58 (2) ◽  
pp. 546-556
Author(s):  
Mark Kelly Davis ◽  
Ali Nesin
Keyword(s):  
Nilpotent Group ◽  
General Structure ◽  
Nilpotent Groups ◽  
Simple Groups ◽  
Closed Field ◽  
Morley Rank ◽  
Nonnilpotent Group ◽  
Finite Morley Rank ◽  
Torsion Free Subgroup ◽  
Torsion Free

We know quite a lot about the general structure of ω-stable solvable centerless groups of finite Morley rank. Abelian groups of finite Morley rank are also well-understood. By comparison, nonabelian nilpotent groups are a mystery except for the following general results:• An ω1-categorical torsion-free nonabelian nilpotent group is an algebraic group over an algebraically closed field of characteristic 0 [Z3].• A nilpotent group of finite Morley rank is the central product of a definable subgroup of finite exponent and of a definable divisible subgroup [N3].• A divisible nilpotent group of finite Morley rank is the direct product of its torsion part (which is central) and of a torsion-free subgroup [N3].However, we do not understand nilpotent groups of bounded exponent. It seems that the classification of nilpotent (but nonabelian) p-groups of finite Morley rank is impossible. Even the nilpotent groups of Morley rank 2 contain insurmountable difficulties [C], [T] . At first glance, this may seem to be an obstacle to proving the Cherlin-Zil'ber conjecture (“simple groups of finite Morley rank are algebraic groups”). Our purpose in this article is to show that if such a group is a definable subgroup of a nonnilpotent group, then it is possible to obtain a classification within the boundaries of our present knowledge. In this respect, our article may be considered as a relief to those who are trying to classify simple groups of finite Morley rank.Before explicitly stating our result, we need the following definition.

scholarly journals Minimal connected simple groups of finite Morley rank with strongly embedded subgroups

2007 ◽  
Vol 314 (2) ◽  
pp. 581-612 ◽  
Author(s):  
Jeffrey Burdges ◽  
Gregory Cherlin ◽  
Eric Jaligot
Keyword(s):  
Simple Groups ◽  
Morley Rank ◽  
Finite Morley Rank

Groups of finite Morley rank with transitive group automorphisms

1989 ◽  
Vol 54 (3) ◽  
pp. 1080-1082
Author(s):  
Ali Nesin
Keyword(s):  
Finite Order ◽  
Short Note ◽  
Algebraic Groups ◽  
Transitive Group ◽  
Simple Groups ◽  
Morley Rank ◽  
Nontrivial Center ◽  
Finite Morley Rank ◽  
Group Automorphisms

The aim of this short note is to prove the following result:Theorem. Let G be a group of finite Morley rank with Aut G acting transitively on G/{1}. Then G is either abelian or a bad group.Bad groups were first defined by Cherlin [Ch]: these are groups of finite Morley rank without solvable and nonnilpotent connected subgroups. They have been investigated by the author [Ne 1], Borovik [Bo], Corredor [Co], and Poizat and Borovik [Bo-Po]. They are not supposed to exist, but we are far from proving their nonexistence. This is one of the major obstacles to proving Cherlin's conjecture: infinite simple groups of finite Morley rank are algebraic groups.If the group G of the theorem is finite, then it is well known that G ≈ ⊕Zp for some prime p: clearly all elements of G have the same order, say p, a prime. Thus G is a finite p-group, so has a nontrivial center. But Aut G acts transitively; thus G is abelian. Since it has exponent p, G ≈ ⊕Zp.The same proof for infinite G does not work even if it has finite Morley rank, for the following reasons:1) G may not contain an element of finite order.2) Even if G does contain an element of finite order, i.e. if G has exponent p, we do not know if G must have a nontrivial center.

scholarly journals CONJUGACY OF CARTER SUBGROUPS IN GROUPS OF FINITE MORLEY RANK

2008 ◽  
Vol 08 (01) ◽  
pp. 41-92 ◽  
Author(s):  
OLIVIER FRÉCON
Keyword(s):  
Conjugacy Class ◽  
Algebraic Groups ◽  
Simple Groups ◽  
Morley Rank ◽  
Minimal Counterexample ◽  
Finite Morley Rank ◽  
Cartan Subgroups

The Cherlin–Zil'ber Conjecture states that all simple groups of finite Morley rank are algebraic. We prove that any minimal counterexample to this conjecture has a unique conjugacy class of Carter subgroups, which are analogous to Cartan subgroups in algebraic groups.

scholarly journals Structure of Borel subgroups in simple groups of finite Morley rank

2015 ◽  
Vol 208 (1) ◽  
pp. 101-162
Author(s):  
Tuna Altinel ◽  
Jeffrey Burdges ◽  
Olivier Frécon
Keyword(s):  
Simple Groups ◽  
Morley Rank ◽  
Finite Morley Rank

Poly-separated and ω-stable nilpotent groups

1991 ◽  
Vol 56 (2) ◽  
pp. 694-699 ◽  
Author(s):  
Ali Nesin
Keyword(s):  
Nilpotent Group ◽  
Torsion Group ◽  
Nilpotent Groups ◽  
Simple Groups ◽  
Structure Theory ◽  
Morley Rank ◽  
Central Product ◽  
Derived Subgroup ◽  
Finite Morley Rank ◽  
Algebraically Closed Fields

Let π be a set of primes. We will call a group π-separated if it can be decomposed as a central product of a π-torsion group of bounded exponent and a π-radicable group. It is easy to see that an abelian π-separated group can in fact be decomposed as a direct product of bounded and π-radicable factors (Lemma 1.1 below). A poly-π-separated group is one which can be obtained from π-separated groups by forming a finite series of group extensions. We will show here:Theorem 1. Every poly-π-separated nilpotent group is π-separated.The need for such a result arises in model theory in the case that π is the set of all primes, in which case we refer simply to separated and poly-separated groups. In connection with the conjecture that ω-stable simple groups are algebraic, it is useful to have a structure theory for solvable ω-stable groups analogous to the theory available in the algebraic case over algebraically closed fields. In particular the structure of nilpotent ω-stable groups is of interest, for example in connection with the known result [Zi1], [Ne] that the derived subgroup of a connected solvable ω-stable group of finite Morley rank is nilpotent.As a model-theoretic application of Theorem 1 we obtain:Theorem 2. If G is an ω-stable nilpotent group then G may be decomposed as a central product B * D with B and D 0-definable subgroups, B torsion of bounded exponent, and D radicable. In particular, B and D are ω-stable. Furthermore, ω · rk(B ∩ D) ≤ rk D.Corollary. The ω-stable groups of finite Morley rank are exactly the central products B * D of ω-stable nilpotent groups of finite Morley rank with B torsion of bounded exponent, D radicable, and B ∩ D finite.In addition to the purely algebraic Theorem 1, these results depend on Macintyre's characterization [Mac] of the ω-stable abelian groups as exactly the separated ones.

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