let f be Form of V,V; :: thesis: ( f is hermitan & f is additiveSAF implies f is additiveFAF )
assume A1: ( f is hermitan & f is additiveSAF ) ; :: thesis: f is additiveFAF
let v1 be Vector of V; :: according to BILINEAR:def 11 :: thesis: FunctionalFAF (f,v1) is additive
set F = FunctionalFAF (f,v1);
set F2 = FunctionalSAF (f,v1);
now :: thesis: for x, y being Vector of V holds (FunctionalFAF (f,v1)) . (x + y) = ((FunctionalFAF (f,v1)) . x) + ((FunctionalFAF (f,v1)) . y)
let x, y be Vector of V; :: thesis: (FunctionalFAF (f,v1)) . (x + y) = ((FunctionalFAF (f,v1)) . x) + ((FunctionalFAF (f,v1)) . y)
thus (FunctionalFAF (f,v1)) . (x + y) = f . (v1,(x + y)) by BILINEAR:8
.= (f . ((x + y),v1)) *' by A1
.= ((FunctionalSAF (f,v1)) . (x + y)) *' by BILINEAR:9
.= (((FunctionalSAF (f,v1)) . x) + ((FunctionalSAF (f,v1)) . y)) *' by A1, VECTSP_1:def 20
.= ((f . (x,v1)) + ((FunctionalSAF (f,v1)) . y)) *' by BILINEAR:9
.= ((f . (x,v1)) + (f . (y,v1))) *' by BILINEAR:9
.= ((f . (x,v1)) *') + ((f . (y,v1)) *') by COMPLFLD:51
.= (f . (v1,x)) + ((f . (y,v1)) *') by A1
.= (f . (v1,x)) + (f . (v1,y)) by A1
.= ((FunctionalFAF (f,v1)) . x) + (f . (v1,y)) by BILINEAR:8
.= ((FunctionalFAF (f,v1)) . x) + ((FunctionalFAF (f,v1)) . y) by BILINEAR:8 ; :: thesis: verum
end;
hence FunctionalFAF (f,v1) is additive ; :: thesis: verum