is there a name for a gadget with stict unit strict inverses but multiplcation not always defined and associativity holds when both a(bc) and (ab)c are defined BUT neither bracketing existing implies the other exists references? thanks .oooO Jim Stasheff jds@math.unc.edu (UNC) Math-UNC (919)-962-9607 \ ( Chapel Hill NC FAX:(919)-962-2568 \*) 27599-3250 http://www.math.unc.edu/Faculty/jds May 15 - August 15: 146 Woodland Dr Lansdale PA 19446 (215)822-6707