22 Jul
2015
22 Jul
'15
2:29 a.m.
The quadratic equation satisfied by the arrow graph is X^2 = X+2D, not X+2. [The generic dot D is not the terminal object 1 in this category. See p. 267 Conceptual Mathematics, 2nd edition.] Bill [For admin and other information see: http://www.mta.ca/~cat-dist/ ]