theorem Th60: :: FACIRC_1:60

for x, y, c being 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)) )