set vq = VectQuot V,(LKer f);
set vr = VectQuot V,(RKer (f *' ));
set qh = ScalarForm f;
A1: leftker (ScalarForm f) =
leftker (Q*Form f)
by Th69
.=
{(0. (VectQuot V,(LKer f)))}
by BILINEAR:def 24
;
rightker (ScalarForm f) =
rightker (Q*Form f)
by Th59
.=
{(0. (VectQuot V,(RKer (f *' ))))}
by BILINEAR:def 25
.=
{(0. (VectQuot V,(LKer f)))}
by Th59
;
hence A2:
( not ScalarForm f is degenerated-on-left & not ScalarForm f is degenerated-on-right )
by A1, BILINEAR:def 24, BILINEAR:def 25; ScalarForm f is positivediagvalued
let A be Vector of (VectQuot V,(LKer f)); HERMITAN:def 13 ( A <> 0. (VectQuot V,(LKer f)) implies 0 < Re ((ScalarForm f) . A,A) )
assume
A <> 0. (VectQuot V,(LKer f))
; 0 < Re ((ScalarForm f) . A,A)
then
Re ((ScalarForm f) . A,A) <> 0
by A2, Th61;
hence
0 < Re ((ScalarForm f) . A,A)
by Def7; verum