theorem Th35: :: FUNCTOR3:35

for A, B, C being category
for F1, F2 being covariant Functor of A,B
for G1 being covariant Functor of B,C
for e being natural_equivalence of F1,F2 st F1,F2 are_naturally_equivalent holds
( G1 * F1,G1 * F2 are_naturally_equivalent & G1 * e is natural_equivalence of G1 * F1,G1 * F2 )