Another question on Grothendieck

Grothendieck introduces, on the top of p. 209 of the Tohoku paper, the notation U_{i_0..i_p} without explanation and uses it again over the next couple pages. Here {U_i} is an open cover of a space X and I have reason to believe that this stands for the intersection of U_{i_j}. Can anyone confirm this? Or give an alternate explanation? The context is that of a claim that (when A is a sheaf) and "every U_{i_0..i_p} is A-acyclic, then"... and that awfully like the definition of a simple cover. Michael [For admin and other information see: http://www.mta.ca/~cat-dist/ ]