for V1, V2 being free finite-rank Z_Module
for f1, f2 being Function of V1,V2
for b1 being OrdBasis of V1
for b2 being OrdBasis of V2 holds AutMt ((f1 + f2),b1,b2) = (AutMt (f1,b1,b2)) + (AutMt (f2,b1,b2))