let it1, it2 be Function of [:REAL,(Funcs (X, the carrier of Y)):],(Funcs (X, the carrier of Y)); ( ( for a being Real
for f being Element of Funcs (X, the carrier of Y)
for x being Element of X holds (it1 . [a,f]) . x = a * (f . x) ) & ( for a being Real
for f being Element of Funcs (X, the carrier of Y)
for x being Element of X holds (it2 . [a,f]) . x = a * (f . x) ) implies it1 = it2 )
assume that
A3:
for a being Real
for f being Element of Funcs (X, the carrier of Y)
for x being Element of X holds (it1 . [a,f]) . x = a * (f . x)
and
A4:
for a being Real
for f being Element of Funcs (X, the carrier of Y)
for x being Element of X holds (it2 . [a,f]) . x = a * (f . x)
; it1 = it2
hence
it1 = it2
; verum