The axiom of choice need not hold in a topos, and the law of the excluded middle need not hold.

John Baez

more, much more: toposes, triples and theories (full book pdf)

(Source: math.ucr.edu)

6 notes

  1. kollontaist reblogged this from isomorphismes
  2. davidaedwards reblogged this from isomorphismes
  3. isomorphismes posted this