theorem Th13: :: MOD_2:13
for R being Ring
for G1, G2, G3 being LeftMod of R
for G being Morphism of G2,G3
for F being Morphism of G1,G2
for g being Function of G2,G3
for f being Function of G1,G2 st G = LModMorphismStr(# G2,G3,g #) & F = LModMorphismStr(# G1,G2,f #) holds
( G *' F = LModMorphismStr(# G1,G3,(g * f) #) & G * F = LModMorphismStr(# G1,G3,(g * f) #) )