IUMJ

Title: Contractive idempotents on locally compact quantum groups

Authors: Matthias Neufang, Pekka Salmi, Adam Skalski and Nico Spronk

Issue: Volume 62 (2013), Issue 6, 1983-2002

Abstract:

A general form of contractive idempotent functionals on coamenable locally compact quantum groups is obtained, generalising the result of Greenleaf on contractive measures on locally compact groups. The image of a convolution operator associated with a contractive idempotent is shown to be a ternary ring of operators. As a consequence, a one-to-one correspondence between contractive idempotents and a certain class of ternary rings of operators is established.