
theorem
  for x,b being non pair set for s being State of BitCompCirc(x,b) for
  a1,a2 being Element of BOOLEAN st a1 = s.x & a2 = s.b holds (Following s).
  CompOutput(x,b) = 'not' a1 'xor' a2 & (Following s).IncrementOutput(x,b) =
  'not' a1 '&' a2 & (Following s).x = a1 & (Following s).b = a2 by Th46,Th50;
