Degrees of irreducible representations of direct products of nonabelian simple groups

Kamal Aziziheris1,2
1Department of Pure Mathematics, Faculty of Mathematical Sciences, University of Tabriz, Tabriz, Iran
2School of Mathematics, Institute for Research in Fundamental Sciences (IPM), Tehran, Iran

Tóm tắt

For a finite group G, let the character degree set of G, denoted by $$\mathrm{cd}(G)$$, be the set of the degrees of all irreducible complex representations of G. In the present paper, the structure of finite groups whose character degree sets coincide with the character degree sets of direct product of nonabelian simple groups will be studied. For a finite group S and a positive integer n, let $$S^{n}$$ be the direct product of n copies of S. We prove that if G is a finite group with $$\mathrm{cd}(G)=\mathrm{cd}(H)$$, where $$\begin{aligned}&H\in \{\mathrm{PSL}_{3}(q)^{n}(q=2^{\alpha }\geqslant 4, 3\not \mid q-1), \mathrm{PSU}_{3}(q)^{n}(q=2^{\alpha }\geqslant 4, 3\not \mid q+1), \\&\quad M_{11}^{n} (1\leqslant n\leqslant 2), M_{23}^{n}, J_{1}^{n}, J_{2}^{n}, J_{3}^{n}, J_{4}^{n}\}, \end{aligned}$$then G is a quasi perfect group. This extends the first step of Huppert’s Conjecture to the direct product of simple groups. This conjecture states that the nonabelian simple groups are uniquely determined up to an abelian direct factor by the set of character degrees.

Tài liệu tham khảo

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