Decomposition numbers of finite classical groups for linear primes.
Let be a regular prehomogeneous vector space (abbreviated to ), where is a reductive algebraic group over . If is a decomposition of into irreducible representations, then, in general, the PV’s are no longer regular. In this paper we introduce the notion of quasi-irreducible (abbreviated to -irreducible), and show first that for completely -reducible ’s, the -isotypic components are intrinsically defined, as in ordinary representation theory. We also show that, in an appropriate...
We study direct decompositions of extensions of rigid completely decomposable groups by finite primary groups. These decompositions are unique and can be found by finite procedures. By passing to certain quotients the determination of the direct decompositions is made more efficient.
We find several large classes of equations with the property that every automorphism of the lattice of equational theories of commutative groupoids fixes any equational theory generated by such equations, and every equational theory generated by finitely many such equations is a definable element of the lattice. We conjecture that the lattice has no non-identical automorphisms.
In this article, direct sum decomposition of group is mainly discussed. In the second section, support of element of direct product group is defined and its properties are formalized. It is formalized here that an element of direct product group belongs to its direct sum if and only if support of the element is finite. In the third section, product map and sum map are prepared. In the fourth section, internal and external direct sum are defined. In the last section, an equivalent form of internal...