No Arabic abstract
The branching theorem expresses irreducible character values for the symmetric group $S_n$ in terms of those for $S_{n-1}$, but it gives the values only at elements of $S_n$ having a fixed point. We extend the theorem by providing a recursion formula that handles the remaining cases. It expresses these character values in terms of values for $S_{n-1}$ together with values for $S_n$ that are already known in the recursive process. This provides an alternative to the Murnaghan-Nakayama formula.
Let $R$ be a commutative Noetherian ring with unit. We classify the characters of the group $mathrm{EL}_d (R)$ provided that $d$ is greater than the stable range of the ring $R$. It follows that every character of $mathrm{EL}_d (R)$ is induced from a finite dimensional representation. Towards our main result we classify $mathrm{EL}_d (R)$-invariant probability measures on the Pontryagin dual group of $R^d$.
The structure of the automorphism group of the sandwich semigroup IS_n is described in terms of standard group constructions.
In this paper we give a Casimir Invariant for the Symmetric group $S_n$. Furthermore we obtain and present, for the first time in the literature, explicit formulas for the matrices of the standard representation in terms of the matrices of the permutation representation.
We compute the BNS-invariant for the pure symmetric automorphism groups of right-angled Artin groups. We use this calculation to show that the pure symmetric automorphism group of a right-angled Artin group is itself not a right-angled Artin group provided that its defining graph contains a separating intersection of links.
A graph $Ga=(V,E)$ is called a Cayley graph of some group $T$ if the automorphism group $Aut(Ga)$ contains a subgroup $T$ which acts on regularly on $V$. If the subgroup $T$ is normal in $Aut(Ga)$ then $Ga$ is called a normal Cayley graph of $T$. Let $r$ be an odd prime. Fang et al. cite{FMW} proved that, with a finite number of exceptions for finite simple group $T$, every connected symmetric Cayley graph of $T$ of valency $r$ is normal. In this paper, employing maximal factorizations of finite almost simple groups, we work out a possible list of those exceptions for $T$.