
theorem Th80:
  for x,y,z being set holds [<*x,y*>,and2a] in InnerVertices
GFA2CarryStr(x,y,z) & [<*y,z*>,and2c] in InnerVertices GFA2CarryStr(x,y,z) & [
<*z,x*>,nor2] in InnerVertices GFA2CarryStr(x,y,z) & GFA2CarryOutput(x,y,z) in
  InnerVertices GFA2CarryStr(x,y,z)
proof
  let x,y,z be set;
  set f1 = and2a, f2 = and2c, f3 = nor2;
  set xy = [<*x,y*>,f1], yz = [<*y,z*>,f2], zx = [<*z,x*>,f3];
  InnerVertices GFA2CarryStr(x,y,z) = {xy,yz,zx} \/ {GFA2CarryOutput(x,y,z
  )} by Th74
    .= {xy,yz,zx,GFA2CarryOutput(x,y,z)} by ENUMSET1:6;
  hence thesis by ENUMSET1:def 2;
end;
