let x, y, c be object ; for f being Function of (2 -tuples_on BOOLEAN),BOOLEAN holds
( x in the carrier of (2GatesCircStr (x,y,c,f)) & y in the carrier of (2GatesCircStr (x,y,c,f)) & c in the carrier of (2GatesCircStr (x,y,c,f)) )
let f be Function of (2 -tuples_on BOOLEAN),BOOLEAN; ( x in the carrier of (2GatesCircStr (x,y,c,f)) & y in the carrier of (2GatesCircStr (x,y,c,f)) & c in the carrier of (2GatesCircStr (x,y,c,f)) )
set S1 = 1GateCircStr (<*x,y*>,f);
set S2 = 1GateCircStr (<*[<*x,y*>,f],c*>,f);
A1:
c in the carrier of (1GateCircStr (<*[<*x,y*>,f],c*>,f))
by Th43;
( x in the carrier of (1GateCircStr (<*x,y*>,f)) & y in the carrier of (1GateCircStr (<*x,y*>,f)) )
by Th43;
hence
( x in the carrier of (2GatesCircStr (x,y,c,f)) & y in the carrier of (2GatesCircStr (x,y,c,f)) & c in the carrier of (2GatesCircStr (x,y,c,f)) )
by A1, Th20; verum