let y be object ; TARSKI:def 3 ( not y in rng ((AffineMap ((1 / (2 * PI)),0)) | (R^1 E)) or y in ].0,1.[ )
assume
y in rng ((AffineMap ((1 / (2 * PI)),0)) | (R^1 E))
; y in ].0,1.[
then consider x being object such that
A1:
x in dom ((AffineMap ((1 / (2 * PI)),0)) | (R^1 E))
and
A2:
((AffineMap ((1 / (2 * PI)),0)) | (R^1 E)) . x = y
by FUNCT_1:def 3;
reconsider x = x as Real by A1;
A3: y =
(AffineMap ((1 / (2 * PI)),0)) . x
by A1, A2, Lm28, FUNCT_1:49
.=
((1 / (2 * PI)) * x) + 0
by FCONT_1:def 4
.=
x / (2 * PI)
by XCMPLX_1:99
;
then reconsider y = y as Real ;
x <= PI
by A1, Lm28, XXREAL_1:2;
then
y <= (1 * PI) / (2 * PI)
by A3, XREAL_1:72;
then
y <= 1 / 2
by XCMPLX_1:91;
then A4:
y < 1
by XXREAL_0:2;
0 < x
by A1, Lm28, XXREAL_1:2;
hence
y in ].0,1.[
by A3, A4, XXREAL_1:4; verum