Department of Mathematics, Pennsylvania State University, University Park, Pennsylvania 16802 ; Department of Mathematics, 2565 McCarthy Mall, University of Hawaii, Manoa, Honolulu, Hawaii 96822-2273
Abstract:
We show that every metric space with bounded geometry uniformly embeds into a direct sum of spaces ('s going off to infinity). In particular, every sequence of expanding graphs uniformly embeds into such a reflexive Banach space even though no such sequence uniformly embeds into a fixed space. In the case of discrete groups we prove the analogue of a--menability - the existence of a metrically proper affine isometric action on a direct sum of spaces.