for M being non empty set
for V being ComplexNormSpace
for f1, f2 being PartFunc of M,V
for x being Element of M st f1 is total & f2 is total holds
( (f1 + f2) /. x = (f1 /. x) + (f2 /. x) & (f1 - f2) /. x = (f1 /. x) - (f2 /. x) )