let f be one-to-one continuous Function of R^1,R^1; ( for x, y being Point of I[01]
for p, q, fx, fy being Real st x = p & y = q & p < q & fx = f . x & fy = f . y holds
fx < fy or for x, y being Point of I[01]
for p, q, fx, fy being Real st x = p & y = q & p < q & fx = f . x & fy = f . y holds
fx > fy )
A1: [.0,1.] /\ (dom f) =
[.0,1.] /\ the carrier of R^1
by FUNCT_2:def 1
.=
[.0,1.]
by BORSUK_1:1, BORSUK_1:40, TOPMETR:20, XBOOLE_1:28
;
reconsider g = f as PartFunc of REAL,REAL by TOPMETR:17;
per cases
( g | [.0,1.] is increasing or g | [.0,1.] is decreasing )
by Lm5;
suppose
g | [.0,1.] is
increasing
;
( for x, y being Point of I[01]
for p, q, fx, fy being Real st x = p & y = q & p < q & fx = f . x & fy = f . y holds
fx < fy or for x, y being Point of I[01]
for p, q, fx, fy being Real st x = p & y = q & p < q & fx = f . x & fy = f . y holds
fx > fy )hence
( for
x,
y being
Point of
I[01] for
p,
q,
fx,
fy being
Real st
x = p &
y = q &
p < q &
fx = f . x &
fy = f . y holds
fx < fy or for
x,
y being
Point of
I[01] for
p,
q,
fx,
fy being
Real st
x = p &
y = q &
p < q &
fx = f . x &
fy = f . y holds
fx > fy )
by A1, BORSUK_1:40, RFUNCT_2:20;
verum end; suppose
g | [.0,1.] is
decreasing
;
( for x, y being Point of I[01]
for p, q, fx, fy being Real st x = p & y = q & p < q & fx = f . x & fy = f . y holds
fx < fy or for x, y being Point of I[01]
for p, q, fx, fy being Real st x = p & y = q & p < q & fx = f . x & fy = f . y holds
fx > fy )hence
( for
x,
y being
Point of
I[01] for
p,
q,
fx,
fy being
Real st
x = p &
y = q &
p < q &
fx = f . x &
fy = f . y holds
fx < fy or for
x,
y being
Point of
I[01] for
p,
q,
fx,
fy being
Real st
x = p &
y = q &
p < q &
fx = f . x &
fy = f . y holds
fx > fy )
by A1, BORSUK_1:40, RFUNCT_2:21;
verum end; end;