let V be ComplexLinearSpace; :: thesis: for M being Subset of V
for z1, z2 being Complex st ex r1, r2 being Real st
( z1 = r1 & z2 = r2 & r1 >= 0 & r2 >= 0 ) & M is convex holds
(z1 * M) + (z2 * M) c= (z1 + z2) * M
let M be Subset of V; :: thesis: for z1, z2 being Complex st ex r1, r2 being Real st
( z1 = r1 & z2 = r2 & r1 >= 0 & r2 >= 0 ) & M is convex holds
(z1 * M) + (z2 * M) c= (z1 + z2) * M
let z1, z2 be Complex; :: thesis: ( ex r1, r2 being Real st
( z1 = r1 & z2 = r2 & r1 >= 0 & r2 >= 0 ) & M is convex implies (z1 * M) + (z2 * M) c= (z1 + z2) * M )
assume that
A1:
ex r1, r2 being Real st
( z1 = r1 & z2 = r2 & r1 >= 0 & r2 >= 0 )
and
A2:
M is convex
; :: thesis: (z1 * M) + (z2 * M) c= (z1 + z2) * M
consider r1, r2 being Real such that
B1:
( z1 = r1 & z2 = r2 & r1 >= 0 & r2 >= 0 )
by A1;
per cases
( M is empty or not M is empty )
;
suppose A3:
not
M is
empty
;
:: thesis: (z1 * M) + (z2 * M) c= (z1 + z2) * Mper cases
( z1 = 0 or z2 = 0 or ( z1 <> 0 & z2 <> 0 ) )
;
suppose A6:
(
z1 <> 0 &
z2 <> 0 )
;
:: thesis: (z1 * M) + (z2 * M) c= (z1 + z2) * Mthen A7:
(
r1 + r2 > 0 + 0 &
r1 + r2 > r1 &
r1 + r2 > r2 )
by B1, XREAL_1:31;
then
(
0 < r1 / (r1 + r2) &
r1 / (r1 + r2) < 1 &
0 < r2 / (r1 + r2) &
r2 / (r1 + r2) < 1 )
by B1, A6, XREAL_1:191;
then
((z1 / (z1 + z2)) * M) + ((1r - (z1 / (z1 + z2))) * M) c= M
by B1, A2, Th204;
then A10:
(z1 + z2) * (((z1 / (z1 + z2)) * M) + ((1r - (z1 / (z1 + z2))) * M)) c= (z1 + z2) * M
by Lm206;
A11:
(z1 + z2) * ((z1 / (z1 + z2)) * M) =
((z1 / (z1 + z2)) * (z1 + z2)) * M
by Lm204
.=
z1 * M
by B1, A7, XCMPLX_1:88
;
1
- (r1 / (r1 + r2)) = ((r1 + r2) / (r1 + r2)) - (r1 / (r1 + r2))
by A7, XCMPLX_1:60;
then
1
- (r1 / (r1 + r2)) = ((r1 + r2) - r1) / (r1 + r2)
;
then (z1 + z2) * ((1r - (z1 / (z1 + z2))) * M) =
((z2 / (z1 + z2)) * (z1 + z2)) * M
by B1, Lm204
.=
z2 * M
by B1, A7, XCMPLX_1:88
;
hence
(z1 * M) + (z2 * M) c= (z1 + z2) * M
by A10, A11, Lm205;
:: thesis: verum end; end; end; end;