Basic Sets of Brauer Characters of finite groups of Lie type, III.
The set of invariant symmetric bilinear forms on irreducible modules over fields of characteristic zero for certain groups is studied. Results are obtained under the presence in a finite group of elements of order four whose square is central. In particular, we find that the relevant modules for the groups mentioned in the title always accept an invariant symmetric bilinear form under which the module admits an orthonormal basis.
Let be a finite group. Let be the first column of the ordinary character table of . We will show that if , then . As a consequence, we show that the projective general unitary groups are uniquely determined by the structure of their complex group algebras.