Felipe Román, María Josefa; Kazarin, Lev S.; Martínez-Pastor, Ana; Sotomayor, Víctor(Springer-Verlag, 2020-12)
[EN] Let the group G = AB be the product of subgroupsAandB, and letpbe a prime. We prove thatpdoes not divide the conjugacy class size (index) of eachp-regular element of prime power order x is an element of A boolean OR ...
[EN] The main result in the paper states the following: Let π be a set of odd primes. Let the finite group G=AB be the product of a π -decomposable subgroup A=Oπ(A)×Oπ′(A) and a π -subgroup B . Then Oπ(A)⩽Oπ(G); ...
[EN] Let the group G = AB be a product of two π-decomposable subgroups A = Oπ(A) × Oπ′ (A) and B = Oπ(B) × Oπ′ (B) where π is a set of primes. The authors conjecture that Oπ(A)Oπ(B) = Oπ(B)Oπ(A) if π is a set of odd primes. ...
Felipe Román, María Josefa; Martínez-Pastor, Ana; Sotomayor, Víctor(Springer-Verlag, 2017)
[EN] Let the group G = AB be the product of the subgroups A and B. We determine some structural properties of G when the p-elements in A. B have prime power indices in G, for some prime p. More generally, we also consider ...
Felipe Román, María José; Martínez-Pastor, Ana; Sotomayor, Víctor(Springer-Verlag, 2020-02)
[EN] We provide structural criteria for some finite factorised groups G = AB when the conjugacy class sizes in G of certain pi-elements in A boolean OR B are either pi-numbers or pi'-numbers, for a set of primes pi. In ...
Sotomayor, Víctor; Felipe Román, María Josefa; Martínez-Pastor, Ana(Springer-Verlag, 2019-02)
[EN] An element g of a finite group G is said to be vanishing inG if there exists an irreducible character of G such that (g)=0; in this case, g is also called a zero of G. The aim of this paper is to obtain structural ...