In this paper we introduce the concept of α-commutator which its definition is based on generalized conjugate classes. With this notion, α-nilpotent groups, α-solvable groups, nilpotency and solvability of groups related to the automorphism are defined. N(G) and S(G) are the set of all nilpotency classes and the set of all solvability classes for the group G with respect to different automorphi...

We show that the isoperimetric function of a nitely generated nilpotent group of class c is bounded above by a polynomial of degree 2c.

We prove that every finitely generated nilpotent group of class c admits a polynomial isoperimetric function of degree c+1 and a linear upper bound on its filling length function. 1991 Mathematics Subject Classification: 20F05, 20F32, 57M07

Nilpotent injectors have the property that they contain every nilpotent subgroup that they normalize. A. Bialostocki has conjectured [4] that if G is a finite group then all nilpotent injectors of G are conjugate. He has verified his conjecture for the symmetric and alternating groups. The conjecture is also true for soluble groups. The only property of soluble groups used in proving this is C(...

IN this paper we shall study the connection between local and global nilpotency for groups which satisfy certain chain conditions. In the first section, we shall prove that a group satisfying the chain condition on centralizers has a unique maximal normal nilpotent subgroup (the Fitting subgroup), i.e. the group generated by all normal nilpotent subgroups must again be nilpotent. This generaliz...

Dans un article récent [1], Abderezak Ould Houcine montre qu’un groupe superstable résiduellement C pour une pseudo-variété C admet une série normale définissable G = G0⊲G1⊲· · ·⊲Gn telle que Gi/Gi+1 ∈ C pour i < n, et Gn est résoluble ; si G est ω-stable, on peut choisir Gn nilpotent. Nous étendons son résultat aux groupes supersimples, et montrons en même temps qu’on peut toujours prendre Gn ...

We show that the dimension of the minimal nilpotent coadjoint orbit for a complex simple Lie algebra is equal to twice the dual Coxeter number minus two. Let g be a finite dimensional complex simple Lie algebra. We fix a Cartan subalgebra h, a root system ∆ ⊂ h and a set of positive roots ∆+ ⊂ ∆. Let ρ be half the sum of all positive roots. Denote by θ the highest root and normalize the Killing...

The associated evolution operators which map u(0, ·) to u(t, ·) is the family of Fourier multipliers e, e := F e F . (2) Our main result shows that boundedness in L for p 6= 2 is very rare. The evolution operator is L bounded if and only if it consists of simple translations. If the multiplier (2) is an L multiplier then it is an L multiplier for the dual index, p+q = 1. By interpolation it is ...

In this paper, we investigate the structure of the multiplier module of a Hilbert module over a locally C∗-algebra and the relationship between the set of all adjointable operators from a Hilbert A -module E to a Hilbert A module F and the set of all adjointable operators from the multiplier module M(E) of E to the multiplier module M(F ) of F.