Re: A small cartesian closed concrete category

On Thu, 14 Feb 2008 10:07:27 PM EST, PETER EASTHOPE <peasthope@shaw.ca> asked:

Is there a cartesian closed concrete category which is small enough to write out explicitly?

How about the full category of finite sets? Or, if that's not small enough, and you really fancy an example

... made with binary numbers for instance ,

try the skeletal version of the full category of "sets of cardinality < 2" having as only objects the ordinal numbers 0 and 1. Here 0 x A = 0, 1 x A = A, 0^1 = 0, 0^0 = 1, 1^A = 1. In other words, B x A = min(A, B), B^A = max(1-A, B). Happy Valentines's Day! -- Fred