CORE Metadata, citation and similar papers at core.ac.uk Provided by Digital Commons@Wayne State University Wayne State University DigitalCommons@WayneState Mathematics Faculty Research Publications Mathematics 1-1-2009 The Dixmier-Douady Invariant for Dummies Claude Schochet Wayne State University,
[email protected] Recommended Citation C. Shochet, The Dixmier-Douady invariant for dummies, Notices of the American Mathematical Society 56.7 (2009), 809-816. Available at: http://digitalcommons.wayne.edu/mathfrp/16 This Article is brought to you for free and open access by the Mathematics at DigitalCommons@WayneState. It has been accepted for inclusion in Mathematics Faculty Research Publications by an authorized administrator of DigitalCommons@WayneState. The Dixmier-Douady Invariant for Dummies Claude Schochet he Dixmier-Douady invariant is the pri- a map f to the classifying space BG and there is a mary tool in the classification of contin- pullback diagram ∗ uous trace C -algebras. These algebras G --------------------------------------------------------------------------------------------------------------------------------------! G have come to the fore in recent years ? ? ? ? Tbecause of their relationship to twisted y y K-theory and via twisted K-theory to branes, gerbes, T --------------------------------------------------------------------------------------------------------------------------------------! EG and string theory. ? ? This note sets forth the basic properties of ? ? y y the Dixmier-Douady invariant using only classical