2004/02/29 by Kornel Szlachanyi
Mathematics · Physics and Astronomy · #math.QA #math-ph #math.MP #msc:16W30 #msc:81R50
published as J. Algebra 280 (2004) 249-294 · 48 pages, AMS-Latex
arxiv created 2004/11/09 · arxiv updated 2009/12/01
This is an introduction to double algebras which is the structure modelled by the properties of the convolution product in Hopf algebras, weak Hopf algebras and in Hopf algebroids. We show that Hopf algebroids with a Frobenius integral can be characterized as the double algebras in which the two multiplications satisfy distributivity. We discuss questions of duality, antipode, Maschke theorem and examples.