let x, y, c be set ; ( x <> [<*y,c*>,'&'] & y <> [<*c,x*>,'&'] & c <> [<*x,y*>,'&'] & c <> [<*x,y*>,'xor'] implies InputVertices (BitAdderWithOverflowStr (x,y,c)) = {x,y,c} )
assume that
A1:
x <> [<*y,c*>,'&']
and
A2:
y <> [<*c,x*>,'&']
and
A3:
c <> [<*x,y*>,'&']
and
A4:
c <> [<*x,y*>,'xor']
; InputVertices (BitAdderWithOverflowStr (x,y,c)) = {x,y,c}
A5:
InputVertices (2GatesCircStr (x,y,c,'xor')) = {x,y,c}
by A4, FACIRC_1:57;
InputVertices (MajorityStr (x,y,c)) = {x,y,c}
by A1, A2, A3, Th20;
hence
InputVertices (BitAdderWithOverflowStr (x,y,c)) = {x,y,c}
by A5, Th21, CIRCCOMB:47; verum