theorem :: VFUNCT_1:28

for X being set
for C being non empty set
for V being RealNormSpace
for f2 being PartFunc of C,V
for f1 being PartFunc of C,REAL holds
( (f1 (#) f2) | X = (f1 | X) (#) (f2 | X) & (f1 (#) f2) | X = (f1 | X) (#) f2 & (f1 (#) f2) | X = f1 (#) (f2 | X) )