Finite-dimensional pointed Hopf algebras over finite simple groups of Lie type V. Mixed classes in Chevalley and Steinberg groups

Abstract

We show that all classes that are neither semisimple nor unipotent in finite simple Chevalley or Steinberg groups different from $PS{L}_n(q)$ collapse (i.e. are never the support of a finite-dimensional Nichols algebra). As a consequence, we prove that the only finite-dimensional pointed Hopf algebra whose group of group-like elements is $PS{p}_{2n}(q)$, $P{\Omega }_{4n}^{+}(q)$, $P{\Omega }_{4n}^{-}(q)$, ${}^3{D}_4(q)$, $E_7(q)$, $E_8(q)$, $F_4(q)$, or $G_2(q)$ with q even is the group algebra.

Use of CHEVIE for dealing with E6 is introduced. For explicit calculations see version 2. Further minor corrections