Glasnik matematički, Vol. 37 No. 1, 2002.
Original scientific paper
Notes on Galois algebras
George Szeto
Lianyong Xue
Abstract
Let B be a ring with 1, C the center of B, and G an automorphism group of B of order n for some integer n. Assume B is a Galois algebra over R with Galois group G. For a nonzero idempotent e R, it the rank of Be over Ce is defined and equal to the order of H|Be where H = {g G | g(c) = c for each c C}, then Be is a central Galois algebra with Galois group H|Be. This generalizes the F. R. DeMeyer and T. Kanzaki theorems for Galois algebras. Moreover, a structure theorem for a Galois algebra is given in terms of the concept of the rank of projective module.
Keywords
Galois extensions; Galois algebras; central Galois extensions; separable extensions; Azumaya algebras; rank of a projective module
Hrčak ID:
4809
URI
Publication date:
1.6.2002.
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