Lp-isometries of Grassmann spaces in\\ factors of type II

Let M be a factor of type II with a faithful normal semifinite tracial weight τ, and P the set of all projections in M. Denote by Pc the Grassmann space of all projections in P with trace c, where c is a positive real number. The aim of this paper is to describe the general form of Lp-isometries between Grassmann spaces in a factor of type II. Moreover, we prove that, when $0