Almost all extraspecial p-groups are Swan groups

Let P be an extraspecial p-group which is neither dihedral of order 8, nor of odd order p^3 and exponent p. Let G be a finite group having P as a Sylow p-subgroup. Then the mod-p cohomology ring of G coincides with that of the normalizer N_G(P).Comment: 5 page

Extendible characters and monomial groups of odd order

Let $G$ be a finite $p$-solvable group, where $p$ is an odd prime. We establish a connection between extendible irreducible characters of subgroups of $G$ that lie under monomial characters of $G$ and nilpotent subgroups of $G$. We also provide a way to get ``good'' extendible irreducible characters inside subgroups of $G$. As an application, we show that every normal subgroup $N$ of a finite monomial odd $p, q$-group $G$, that has nilpotent length less than or equal to 3, is monomial

The continuity of pp-rationality and a lower bound for p′p'-degree characters of finite groups

Let $p$ be a prime and $G$ a finite group. We propose a strong bound for the number of $p'$-degree irreducible characters of $G$ in terms of the commutator factor group of a Sylow $p$-subgroup of $G$. The bound arises from a recent conjecture of Navarro and Tiep [NT21] on fields of character values and a phenomenon called the continuity of $p$-rationality level of $p'$-degree characters. This continuity property in turn is predicted by the celebrated McKay-Navarro conjecture [Nav04]. We achieve both the bound and the continuity property for $p=2$.Comment: 22 pages. To appear in TAM

A characterization of the unitary and symplectic groups over finite fields of characteristic at least 55

The following characterization is obtained: THEOREM. Let G be a finite group generated by a conjugacy class D of subgroups of prime order p ^ 5, such that for any choice of distinct A and B in D, the subgroup generated by A and B is isomorphic to Zp x Zp, L2(pm) or SL2(pm), where m depends on A and B. Assume G has no nontrivial solvable normal subgroup. Then G is isomorphic to Spn(q) or Un(q) for some power q of p

On the characters of the Sylow p-subgroups of untwisted Chevalley groups Y_n(p^a)

Let $UY_n(q)$ be a Sylow p-subgroup of an untwisted Chevalley group $Y_n(q)$ of rank n defined over $\mathbb{F}_q$ where q is a power of a prime p. We partition the set $Irr(UY_n(q))$ of irreducible characters of $UY_n(q)$ into families indexed by antichains of positive roots of the root system of type $Y_n$. We focus our attention on the families of characters of $UY_n(q)$ which are indexed by antichains of length 1. Then for each positive root $\alpha$ we establish a one to one correspondence between the minimal degree members of the family indexed by $\alpha$ and the linear characters of a certain subquotient $\overline{T}_\alpha$ of $UY_n(q)$. For $Y_n = A_n$ our single root character construction recovers amongst other things the elementary supercharacters of these groups. Most importantly though this paper lays the groundwork for our classification of the elements of $Irr(UE_i(q))$, $6 \le i \le 8$ and $Irr(UF_4(q))$

Radical \u3cem\u3ep\u3c/em\u3e-chains in L\u3csub\u3e3\u3c/sub\u3e(2).

The McKay-Alperin-Dade Conjecture, which has not been finally verified, predicts the number of complex irreducible characters in various p-blocks of a finite group G as an alternating sum of the numbers of characters in related p-blocks of certain subgroups of G. The sub-groups involved are the normalizers of representatives of conjugacy classes of radical p-chains of G. For this reason, it is of interest to study radical p-chains. In this thesis, we examine the group L3(2) and determine representatives of the conjugacy classes of radical p-subgroups and radical p-chains for the primes p = 2, 3, and 7. We then determine the structure of the normalizers of these subgroups and chains