most recent 30 from http://mathoverflow.net 2013-05-19T09:19:31Z http://mathoverflow.net/feeds/user/16703 http://www.creativecommons.org/licenses/by-nc/2.5/rdf http://mathoverflow.net/questions/71153/pairwise-orthogonal-projections-in-c-algebras Joachim Gryn 2011-07-24T21:19:46Z 2011-07-25T07:02:29Z

<p>Is every non-zero projection in a C*-algebra $A$ a supremum or infimum (at least majorized by / majorizes) a family of pairwise orthogonal non-zero projections in $A$? </p> <p>PS. Are there any cheap ways to generate abelian sub C*-algebras of a given C*-algebra (of course, having in mind Akemann's example of a non-separable C*-algebra with each abelian sub-C*-algebra separable)?</p>

http://mathoverflow.net/questions/71153/pairwise-orthogonal-projections-in-c-algebras/71159#71159 Joachim Gryn 2011-07-24T23:13:07Z 2011-07-24T23:13:07Z

Thanks. I want projections (mutually orthogonal) to generate abelian sub C*-algebras. In fact, I am interested in the ways of producing them.