Isoperimetric Functions of Groups and Computational Complexity of the Word Problem

Abstract

J.-C. Birget, A. Yu Ol'shanskii, E. Rips, M. V. Sapir, Isoperimetric Functions of Groups and Computational Complexity of the Word Problem, Annals of Mathematics, Second Series, Vol. 156, No. 2 (Sep., 2002), pp. 467-518