let a, b be real number ; ( a <= b implies for t1, t2 being Point of (Closed-Interval-TSpace a,b) holds L[01] t1,t2 is continuous Function of (Closed-Interval-TSpace 0 ,1),(Closed-Interval-TSpace a,b) )
assume A1:
a <= b
; for t1, t2 being Point of (Closed-Interval-TSpace a,b) holds L[01] t1,t2 is continuous Function of (Closed-Interval-TSpace 0 ,1),(Closed-Interval-TSpace a,b)
let t1, t2 be Point of (Closed-Interval-TSpace a,b); L[01] t1,t2 is continuous Function of (Closed-Interval-TSpace 0 ,1),(Closed-Interval-TSpace a,b)
reconsider r1 = t1, r2 = t2 as Real by A1, Lm2;
deffunc H1( Element of REAL ) -> Element of REAL = ((r2 - r1) * $1) + r1;
consider L being Function of REAL ,REAL such that
A2:
for r being Real holds L . r = H1(r)
from FUNCT_2:sch 4();
reconsider f = L as Function of R^1 ,R^1 by TOPMETR:24;
A3:
for s being Point of (Closed-Interval-TSpace 0 ,1)
for w being Point of R^1 st s = w holds
(L[01] t1,t2) . s = f . w
A5:
[.0 ,1.] = the carrier of (Closed-Interval-TSpace 0 ,1)
by TOPMETR:25;
A6:
f is continuous
by A2, TOPMETR:28;
for s being Point of (Closed-Interval-TSpace 0 ,1) holds L[01] t1,t2 is_continuous_at s
proof
let s be
Point of
(Closed-Interval-TSpace 0 ,1);
L[01] t1,t2 is_continuous_at s
reconsider w =
s as
Point of
R^1 by A5, TARSKI:def 3, TOPMETR:24;
for
G being
Subset of
(Closed-Interval-TSpace a,b) st
G is
open &
(L[01] t1,t2) . s in G holds
ex
H being
Subset of
(Closed-Interval-TSpace 0 ,1) st
(
H is
open &
s in H &
(L[01] t1,t2) .: H c= G )
proof
let G be
Subset of
(Closed-Interval-TSpace a,b);
( G is open & (L[01] t1,t2) . s in G implies ex H being Subset of (Closed-Interval-TSpace 0 ,1) st
( H is open & s in H & (L[01] t1,t2) .: H c= G ) )
assume
G is
open
;
( not (L[01] t1,t2) . s in G or ex H being Subset of (Closed-Interval-TSpace 0 ,1) st
( H is open & s in H & (L[01] t1,t2) .: H c= G ) )
then consider G0 being
Subset of
R^1 such that A7:
G0 is
open
and A8:
G0 /\ ([#] (Closed-Interval-TSpace a,b)) = G
by TOPS_2:32;
A9:
f is_continuous_at w
by A6, TMAP_1:49;
assume
(L[01] t1,t2) . s in G
;
ex H being Subset of (Closed-Interval-TSpace 0 ,1) st
( H is open & s in H & (L[01] t1,t2) .: H c= G )
then
f . w in G
by A3;
then
f . w in G0
by A8, XBOOLE_0:def 4;
then consider H0 being
Subset of
R^1 such that A10:
H0 is
open
and A11:
w in H0
and A12:
f .: H0 c= G0
by A7, A9, TMAP_1:48;
now reconsider H =
H0 /\ ([#] (Closed-Interval-TSpace 0 ,1)) as
Subset of
(Closed-Interval-TSpace 0 ,1) ;
take H =
H;
( H is open & s in H & (L[01] t1,t2) .: H c= G )thus
H is
open
by A10, TOPS_2:32;
( s in H & (L[01] t1,t2) .: H c= G )thus
s in H
by A11, XBOOLE_0:def 4;
(L[01] t1,t2) .: H c= Gthus
(L[01] t1,t2) .: H c= G
verumproof
let t be
set ;
TARSKI:def 3 ( not t in (L[01] t1,t2) .: H or t in G )
assume
t in (L[01] t1,t2) .: H
;
t in G
then consider r being
set such that
r in dom (L[01] t1,t2)
and A13:
r in H
and A14:
t = (L[01] t1,t2) . r
by FUNCT_1:def 12;
A15:
r in the
carrier of
(Closed-Interval-TSpace 0 ,1)
by A13;
reconsider r =
r as
Point of
(Closed-Interval-TSpace 0 ,1) by A13;
r in dom (L[01] t1,t2)
by A15, FUNCT_2:def 1;
then A16:
t in (L[01] t1,t2) .: the
carrier of
(Closed-Interval-TSpace 0 ,1)
by A14, FUNCT_1:def 12;
reconsider p =
r as
Point of
R^1 by A5, TARSKI:def 3, TOPMETR:24;
p in [#] R^1
;
then A17:
p in dom f
by FUNCT_2:def 1;
(
t = f . p &
p in H0 )
by A3, A13, A14, XBOOLE_0:def 4;
then
t in f .: H0
by A17, FUNCT_1:def 12;
hence
t in G
by A8, A12, A16, XBOOLE_0:def 4;
verum
end; end;
hence
ex
H being
Subset of
(Closed-Interval-TSpace 0 ,1) st
(
H is
open &
s in H &
(L[01] t1,t2) .: H c= G )
;
verum
end;
hence
L[01] t1,
t2 is_continuous_at s
by TMAP_1:48;
verum
end;
hence
L[01] t1,t2 is continuous Function of (Closed-Interval-TSpace 0 ,1),(Closed-Interval-TSpace a,b)
by TMAP_1:49; verum