{ "id": "math/0611349", "version": "v2", "published": "2006-11-12T12:45:05.000Z", "updated": "2008-02-18T14:04:59.000Z", "title": "Injective and projective Hilbert C*-modules, and C*-algebras of compact operators", "authors": [ "Michael Frank", "Vern I. Paulsen" ], "comment": "28 pages, Proposition 3.4 corrected after receiving remarks from Hanfeng Li, thanks for pointing out the errors. Some minor corrections in formulations. 15 references added", "categories": [ "math.OA", "math.KT" ], "abstract": "We consider projectivity and injectivity of Hilbert C*-modules in the categories of Hilbert C*-(bi-)modules over a fixed C*-algebra of coefficients (and another fixed C*-algebra represented as bounded module operators) and bounded (bi-)module morphisms, either necessarily adjointable or arbitrary ones. As a consequence of these investigations, we obtain a set of equivalent conditions characterizing C*-subalgebras of C*-algebras of compact operators on Hilbert spaces in terms of general properties of Hilbert C*-modules over them. Our results complement results recently obtained by B. Magajna, J. Schweizer and M. Kusuda. In particular, all Hilbert C*-(bi-)modules over C*-algebras of compact operators on Hilbert spaces are both injective and projective in the categories we consider. For more general C*-algebras we obtain classes of injective and projective Hilbert C*-(bi-)modules.", "revisions": [ { "version": "v2", "updated": "2008-02-18T14:04:59.000Z" } ], "analyses": { "subjects": [ "46L08", "46H25" ], "keywords": [ "compact operators", "projective hilbert", "hilbert spaces", "results complement results", "categories" ], "note": { "typesetting": "TeX", "pages": 28, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2006math.....11349F" } } }