theorem Th2: :: MULTOP_1:2

for A, B, C, D being non empty set
for f1, f2 being Function of [:A,B,C:],D st ( for a being Element of A
for b being Element of B
for c being Element of C holds f1 . [a,b,c] = f2 . [a,b,c] ) holds
f1 = f2