Journals / Turkish Journal of Mathematics / 2007 / Cilt: 31 - Sayı: 4

Induced Mappings on Boolean Algebras of Clopen Sets and on Projections of the C*-Algebra C(X)

Pages
439–451
DOI
—

Abstract

For a compact space X, any group automorphism j of C(X,S1) induces a mapping Q on the Boolean algebra of the clopen subsets of X. We prove that the disjointness of Q equivalent to qj is an orthoisomorphism on the sets of projections of the C*-algebra C(X), when j(-1)=-1. Indeed, Q is a Boolean isomorphism iff qj preserves the product of projections. If X is equipped with a probability measure m, on a certain s-algebra of X, we show (under some condition) that Q preserves the disjoint of clopen subsets, up to sets of measure zero, or equivalently, the mapping qj is m-orthoisomorphism on the projections of the C*-algebra C(X).

Özet

For a compact space X, any group automorphism j of C(X,S1) induces a mapping Q on the Boolean algebra of the clopen subsets of X. We prove that the disjointness of Q equivalent to qj is an orthoisomorphism on the sets of projections of the C*-algebra C(X), when j(-1)=-1. Indeed, Q is a Boolean isomorphism iff qj preserves the product of projections. If X is equipped with a probability measure m, on a certain s-algebra of X, we show (under some condition) that Q preserves the disjoint of clopen subsets, up to sets of measure zero, or equivalently, the mapping qj is m-orthoisomorphism on the projections of the C*-algebra C(X).

Keywords: Unitary, Projections, Almost Isomorphisms, Boolean Algebra, Clopen Subset