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Let $k$ be an algebraically closed field of characteristic not equal to 2 or 3, let $G$ be an almost simple algebraic group of type $F_4$, $G_2$ or $D_4$ and let $theta$ be an automorphism of $G$ of finite order, coprime to the characteristic. In this paper we consider the $theta$-group (in the sense of Vinberg) associated to these choices; we classify the positive rank automorphisms and give their Kac diagrams and we describe the little Weyl group in each case. As a result we show that all such $theta$-groups have KW-sections, confirming a conjecture of Popov in these cases.
Popov has recently introduced an analogue of Jordan classes (packets, or decomposition classes) for the action of a theta-group (G_0,V), showing that they are finitely-many, locally-closed, irreducible unions of G_0-orbits of constant dimension parti
In this paper we initiate the study of the maximal subalgebras of exceptional simple classical Lie algebras g over algebraically closed fields k of positive characteristic p, such that the prime characteristic is good for g. In this paper we deal wit
We generalize the basic results of Vinbergs theta-groups, or periodically graded reductive Lie algebras, to fields of good positive characteristic. To this end we clarify the relationship between the little Weyl group and the (standard) Weyl group. W
We consider algebras with basis numerated by elements of a group $G.$ We fix a function $f$ from $Gtimes G$ to a ground field and give a multiplication of the algebra which depends on $f$. We study the basic properties of such algebras. In particular
We study the higher Frobenius-Schur indicators of the representations of the Drinfeld double of a finite group G, in particular the question as to when all the indicators are integers. This turns out to be an interesting group-theoretic question. We