NNO

I went too far when I said in my recent flame that there was no solution to 1 + X = X in standard set theory. If we take 1 = {0}, where 0 is the empty set and take A + B = A x {0} u B x {1}, then the set {(0,0), (0,0,1), (0,0,1,1), (0,0,1,1,1), ... } satisfies it on the nose, where I use (a,b,c,d,...) for the left associated ((...(a,b),c),d),e),...). I guess typical covariant domain equations have initial solutions, but not final ones in standard set theory. Thanks to Bob Tennent for pointing this out. Note that this is not the Von Neumann NNO. Michael ++++++++++++++++++++++++ Apologies to Mike for sending this late - it got lost temporarily in the shuffle of mailer problems. Bob Rosebrugh ===========================