On a Counterexample to a Conjecture by Blackadar
Publikation: Bidrag til bog/antologi/rapport › Konferencebidrag i proceedings › Forskning › fagfællebedømt
Blackadar conjectured that if we have a split short-exact sequence 0→I→A→C→0 where I is semiprojective then A must be semiprojective. Eilers and Katsura have found a counterexample to this conjecture. Presumably Blackadar asked that the extension be split to make it more likely that semiprojectivity of I would imply semiprojectivity of A. But oddly enough, in all the counterexamples of Eilers and Katsura the quotient map from A to A/I≅C is split. We will show how to modify their examples to find a non-semiprojective C∗-algebra B with a semiprojective ideal J such that B∕J is the complex numbers and the quotient map does not split.
Originalsprog | Engelsk |
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Titel | Operator Algebra and Dynamics : Nordforsk Network Closing Conference, Faroe Islands, May 2012 |
Redaktører | Toke M. Clausen, Søren Eilers, Gunnar Restorff, Sergei Silvestrov |
Forlag | Springer |
Publikationsdato | 2013 |
Sider | 295-303 |
ISBN (Trykt) | 9783642394584 |
ISBN (Elektronisk) | 9783642394591 |
DOI | |
Status | Udgivet - 2013 |
Navn | Springer Proceedings in Mathematics & Statistics |
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Vol/bind | 58 |
ID: 97160488