let X be non empty set ; for f being PartFunc of X,COMPLEX
for r being Real holds
( r (#) (Re f) = Re (r (#) f) & r (#) (Im f) = Im (r (#) f) )
let f be PartFunc of X,COMPLEX; for r being Real holds
( r (#) (Re f) = Re (r (#) f) & r (#) (Im f) = Im (r (#) f) )
let r be Real; ( r (#) (Re f) = Re (r (#) f) & r (#) (Im f) = Im (r (#) f) )
A1:
dom (r (#) (Re f)) = dom (Re f)
by VALUED_1:def 5;
A2:
Im r = 0
by COMPLEX1:def 2;
A3:
dom (Re f) = dom f
by COMSEQ_3:def 3;
A4:
Re r = r
by COMPLEX1:def 1;
A5:
dom (r (#) f) = dom f
by VALUED_1:def 5;
A6:
dom (Re (r (#) f)) = dom (r (#) f)
by COMSEQ_3:def 3;
now let x be
set ;
( x in dom (r (#) (Re f)) implies (r (#) (Re f)) . x = (Re (r (#) f)) . x )A7:
Re (r * (f . x)) = ((Re r) * (Re (f . x))) - ((Im r) * (Im (f . x)))
by COMPLEX1:9;
assume A8:
x in dom (r (#) (Re f))
;
(r (#) (Re f)) . x = (Re (r (#) f)) . xthen A9:
(Re f) . x = Re (f . x)
by A1, COMSEQ_3:def 3;
(Re (r (#) f)) . x = Re ((r (#) f) . x)
by A1, A5, A6, A3, A8, COMSEQ_3:def 3;
then
(Re (r (#) f)) . x = r * (Re (f . x))
by A1, A5, A3, A4, A2, A8, A7, VALUED_1:def 5;
hence
(r (#) (Re f)) . x = (Re (r (#) f)) . x
by A8, A9, VALUED_1:def 5;
verum end;
hence
r (#) (Re f) = Re (r (#) f)
by A1, A5, A6, A3, FUNCT_1:2; r (#) (Im f) = Im (r (#) f)
A10:
dom (r (#) (Im f)) = dom (Im f)
by VALUED_1:def 5;
A11:
dom (Im f) = dom f
by COMSEQ_3:def 4;
A12:
dom (Im (r (#) f)) = dom (r (#) f)
by COMSEQ_3:def 4;
now let x be
set ;
( x in dom (r (#) (Im f)) implies (r (#) (Im f)) . x = (Im (r (#) f)) . x )A13:
Im (r * (f . x)) = ((Im r) * (Re (f . x))) + ((Re r) * (Im (f . x)))
by COMPLEX1:9;
assume A14:
x in dom (r (#) (Im f))
;
(r (#) (Im f)) . x = (Im (r (#) f)) . xthen A15:
(Im f) . x = Im (f . x)
by A10, COMSEQ_3:def 4;
(Im (r (#) f)) . x = Im ((r (#) f) . x)
by A10, A5, A12, A11, A14, COMSEQ_3:def 4;
then
(Im (r (#) f)) . x = r * (Im (f . x))
by A10, A5, A11, A4, A2, A14, A13, VALUED_1:def 5;
hence
(r (#) (Im f)) . x = (Im (r (#) f)) . x
by A14, A15, VALUED_1:def 5;
verum end;
hence
r (#) (Im f) = Im (r (#) f)
by A10, A5, A12, A11, FUNCT_1:2; verum