Date: Fri, 28 Jan 2000 14:50:49 -0500 (EST)
From: Allen Hatcher - Math Prof <hatcher@math.cornell.edu>
Subject: Delta set terminology

     Here's a comment for the discussion list:

Concerning the Delta set terminology: A related issue is what to call the
geometric incarnations of Delta sets. These are CW complexes with special
structure. In Brayton Gray's book they are called "semisimplicial CW
complexes." Does anyone know of other names in the literature?

These geometric objects occur rather often in the algebraic topology
textbook I'm writing, so I wanted a shorter name and chose to call them
"Delta complexes" since they are somewhere between simplicial complexes
and CW complexes, and they are logically the same as Rourke and
Sanderson's Delta sets. I hope the new terminology doesn't muddy the
waters too much. In any event, the geometric concept seems extremely
useful as well as natural, so it deserves to have its own name, and this
is my candidate.

Allen Hatcher