Subject: categories: abcd=cba

From: James Stasheff <[email-masked]>
Date: Fri, 28 Jan 2000 07:21:26 -0500 (EST)

The pentagon relation abc=de
occurs all over the place.
I've just come across 

abcd = cba

for the first time.

Look familiar?

.oooO   Jim Stasheff		[email-masked]
(UNC)   Math-UNC		(919)-962-9607
 \ (    Chapel Hill NC		FAX:(919)-962-2568
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        http://www.math.unc.edu/Faculty/jds