Rearrangements of the Symmetric Group and Enumerative Properties of the Tangent and Secant Numbers.
We introduce the notion of a polar region of a spherical building and use some simple observations about polar regions to give elementary proofs of various fundamental properties of root groups. We combine some of these observations with results of Timmesfeld, Balser and Lytchak to give a new proof of the center conjecture for convex chamber subcomplexes of thick spherical buildings.
The character degree graph of a finite group is the graph whose vertices are the prime divisors of the irreducible character degrees of and two vertices and are joined by an edge if divides some irreducible character degree of . It is proved that some simple groups are uniquely determined by their orders and their character degree graphs. But since the character degree graphs of the characteristically simple groups are complete, there are very narrow class of characteristically simple...
Let be a finite group. An element is called a vanishing element if there exists an irreducible complex character of such that . Denote by the set of orders of vanishing elements of . Ghasemabadi, Iranmanesh, Mavadatpour (2015), in their paper presented the following conjecture: Let be a finite group and a finite nonabelian simple group such that and . Then . We answer in affirmative this conjecture for , where and either , or is a prime number, and , where and either...
Let be a finite group. The main supergraph is a graph with vertex set in which two vertices and are adjacent if and only if or . In this paper, we will show that if and only if , where .