reserve x,y,z,c for object,
  f for Function of 2-tuples_on BOOLEAN, BOOLEAN;
reserve s for State of 2GatesCircuit(x,y,c,f);

theorem
  BitAdderOutput(x,y,c) in InnerVertices BitAdderWithOverflowStr(x,y,c)
& MajorityOutput(x,y,c) in InnerVertices BitAdderWithOverflowStr(x,y,c) by Th21
