Subject: about rectification of homotopy commutative diagram From: Gaucher Philippe Date: Fri, 8 Jun 2007 12:18:17 +0200 Dear all, Consider the small category I: 0->1->2->... Let M be a model category (good enough, proper, etc...). A morphism of M^I looks like a ladder, i.e. a diagram over another small category L(I) having the shape of a ladder. I know how to rectify a homotopy commutative diagram of Ho(M)^L(I), that is how to construct an object of Ho(M^L(I)) sent by the map Ho(M^L(I))->Ho(M)^L(I) to the morphism of M^I we are considering. Is it realistic to think that the same result holds if I is any direct Reedy category ? Thanks in advance. pg.