On Galois Algebras Satisfying the Fundamental Theorem.

Autor: Szeto, George, Xue, Lianyong
Předmět:
Zdroj: Communications in Algebra; Dec2007, Vol. 35 Issue 12, p3979-3985, 7p
Abstrakt: Let B be a Galois algebra over a commutative ring R with Galois group G such that BH is a separable subalgebra of B for each subgroup H of G. Then it is shown that B satisfies the fundamental theorem if and only if B is one of the following three types: (1) B is an indecomposable commutative Galois algebra, (2) B = Re ⊕ R(1 - e) where e and 1 - e are minimal central idempotents in B, and (3) B is an indecomposable Galois algebra such that for each separable subalgebra A, VB(A) = ⊕∑g∈G(A)Jg, and the centers of A and BG(A) are the same where VB(A) is the commutator subring of A in B, Jg = {b ∈ B | bx = g(x)b for each x ∈ B} for a g ∈ G, and G(A) = {g ∈ G | g(a) = a for all a ∈ A}. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index