A1:
( 0 is Point of I[01] & 1 / 2 is Point of I[01] & 1 / 4 is Point of I[01] & 3 / 4 is Point of I[01] & 1 is Point of I[01] )
by BORSUK_1:86;
then reconsider A = [.0 ,(1 / 2).] as non empty compact Subset of I[01] by BORSUK_4:49;
reconsider B = [.(1 / 2),(3 / 4).] as non empty compact Subset of I[01] by A1, BORSUK_4:49;
reconsider C = [.(3 / 4),1.] as non empty compact Subset of I[01] by A1, BORSUK_4:49;
reconsider D = [.(1 / 2),1.] as non empty compact Subset of I[01] by A1, BORSUK_4:49;
reconsider E = [.(1 / 4),(1 / 2).] as non empty compact Subset of I[01] by A1, BORSUK_4:49;
reconsider F = [.0 ,(1 / 4).] as non empty compact Subset of I[01] by A1, BORSUK_4:49;
set T = I[01] ;
set T1 = I[01] | A;
set T2 = I[01] | B;
set T3 = I[01] | C;
set T4 = I[01] | D;
set T5 = I[01] | E;
set T6 = I[01] | F;
A2:
Closed-Interval-TSpace (3 / 4),1 = I[01] | C
by TOPMETR:31;
A3:
Closed-Interval-TSpace (1 / 2),1 = I[01] | D
by TOPMETR:31;
A4:
Closed-Interval-TSpace (1 / 4),(1 / 2) = I[01] | E
by TOPMETR:31;
A5:
Closed-Interval-TSpace (1 / 2),(3 / 4) = I[01] | B
by TOPMETR:31;
A6:
Closed-Interval-TSpace 0 ,(1 / 4) = I[01] | F
by TOPMETR:31;
A7:
Closed-Interval-TSpace 0 ,(1 / 2) = I[01] | A
by TOPMETR:31;
set f = L[01] 0 ,(1 / 2),0 ,(1 / 4);
reconsider f = L[01] 0 ,(1 / 2),0 ,(1 / 4) as continuous Function of (I[01] | A),(I[01] | F) by A6, A7, Th38;
reconsider f = f as continuous Function of (I[01] | A),I[01] by JORDAN6:4;
A8:
for x being Point of (I[01] | A) holds f . x = (1 / 2) * x
set g = L[01] (1 / 2),(3 / 4),(1 / 4),(1 / 2);
reconsider g = L[01] (1 / 2),(3 / 4),(1 / 4),(1 / 2) as continuous Function of (I[01] | B),(I[01] | E) by A4, A5, Th38;
reconsider g = g as continuous Function of (I[01] | B),I[01] by JORDAN6:4;
A9:
for x being Point of (I[01] | B) holds g . x = x - (1 / 4)
set h = L[01] (3 / 4),1,(1 / 2),1;
reconsider h = L[01] (3 / 4),1,(1 / 2),1 as continuous Function of (I[01] | C),(I[01] | D) by A2, A3, Th38;
reconsider h = h as continuous Function of (I[01] | C),I[01] by JORDAN6:4;
A10:
for x being Point of (I[01] | C) holds h . x = (2 * x) - 1
reconsider G = [.0 ,(3 / 4).] as non empty compact Subset of I[01] by A1, BORSUK_4:49;
reconsider TT1 = I[01] | A, TT2 = I[01] | B as SubSpace of I[01] | G by TOPMETR:29, XXREAL_1:34;
set f1 = f;
set g1 = g;
A11: ([#] TT1) \/ ([#] TT2) =
A \/ ([#] TT2)
by PRE_TOPC:def 10
.=
A \/ B
by PRE_TOPC:def 10
.=
[.0 ,(3 / 4).]
by XXREAL_1:174
.=
[#] (I[01] | G)
by PRE_TOPC:def 10
;
A13: ([#] TT1) /\ ([#] TT2) =
A /\ ([#] TT2)
by PRE_TOPC:def 10
.=
A /\ B
by PRE_TOPC:def 10
.=
{(1 / 2)}
by XXREAL_1:418
;
for p being set st p in ([#] TT1) /\ ([#] TT2) holds
f . p = g . p
then consider FF being Function of (I[01] | G),I[01] such that
A15:
( FF = f +* g & FF is continuous )
by A11, BORSUK_2:1;
A16: ([#] (I[01] | G)) \/ ([#] (I[01] | C)) =
G \/ ([#] (I[01] | C))
by PRE_TOPC:def 10
.=
G \/ C
by PRE_TOPC:def 10
.=
[#] I[01]
by BORSUK_1:83, XXREAL_1:174
;
A17: ([#] (I[01] | G)) /\ ([#] (I[01] | C)) =
G /\ ([#] (I[01] | C))
by PRE_TOPC:def 10
.=
G /\ C
by PRE_TOPC:def 10
.=
{(3 / 4)}
by XXREAL_1:418
;
for p being set st p in ([#] (I[01] | G)) /\ ([#] (I[01] | C)) holds
FF . p = h . p
then consider HH being Function of I[01] ,I[01] such that
A19:
( HH = FF +* h & HH is continuous )
by A15, A16, BORSUK_2:1;
for x being Element of I[01] holds HH . x = 3RP . x
proof
let x be
Element of
I[01] ;
:: thesis: HH . x = 3RP . x
A20:
(
0 <= x &
x <= 1 )
by BORSUK_1:86;
per cases
( x < 1 / 2 or x = 1 / 2 or ( x > 1 / 2 & x < 3 / 4 ) or x = 3 / 4 or x > 3 / 4 )
by XXREAL_0:1;
suppose A21:
x < 1
/ 2
;
:: thesis: HH . x = 3RP . xthen
x in [.0 ,(1 / 2).]
by A20, XXREAL_1:1;
then A22:
x is
Point of
(I[01] | A)
by PRE_TOPC:29;
not
x in [.(1 / 2),(3 / 4).]
by A21, XXREAL_1:1;
then
not
x in the
carrier of
(I[01] | B)
by PRE_TOPC:29;
then A23:
not
x in dom g
;
x < 3
/ 4
by A21, XXREAL_0:2;
then
not
x in [.(3 / 4),1.]
by XXREAL_1:1;
then
not
x in the
carrier of
(I[01] | C)
by PRE_TOPC:29;
then
not
x in dom h
;
then HH . x =
FF . x
by A19, FUNCT_4:12
.=
f . x
by A15, A23, FUNCT_4:12
.=
(1 / 2) * x
by A8, A22
.=
3RP . x
by A21, Def9
;
hence
HH . x = 3RP . x
;
:: thesis: verum end; end;
end;
hence
3RP is continuous
by A19, FUNCT_2:113; :: thesis: verum