The book contains carefully written expository and research articles by leaders in the field, including a reprint of the original 1943 paper on C[* algebras by

A locally compact group has the Haagerup property, or is a-T-menable in the sense of Gromov, if it admits a proper isometric action on some affine Hilbert space

`The most important single thing about this conference was that it brought together for the first time representatives of all major groups of users of hypergrou

This monograph draws on two traditions: the algebraic formulation of quantum mechanics as well as quantum field theory, and the geometric theory of classical me