let f be FinSequence of REAL ; for r1, r2 being Real st f = <*r1,r2*> holds
( min f = min r1,r2 & min_p f = IFEQ r1,(min r1,r2),1,2 )
let r1, r2 be Real; ( f = <*r1,r2*> implies ( min f = min r1,r2 & min_p f = IFEQ r1,(min r1,r2),1,2 ) )
assume A1:
f = <*r1,r2*>
; ( min f = min r1,r2 & min_p f = IFEQ r1,(min r1,r2),1,2 )
then A2:
len f = 2
by FINSEQ_1:61;
then A3:
f . 1 >= f . (min_p f)
by Th2;
A4:
f . 2 = r2
by A1, FINSEQ_1:61;
A5:
min_p f in dom f
by A2, Def2;
then A6:
1 <= min_p f
by FINSEQ_3:27;
A7:
f . 2 >= f . (min_p f)
by A2, Th2;
A8:
f . 1 = r1
by A1, FINSEQ_1:61;
A9:
min_p f <= len f
by A5, FINSEQ_3:27;
per cases
( r1 <= r2 or r1 > r2 )
;
suppose
r1 <= r2
;
( min f = min r1,r2 & min_p f = IFEQ r1,(min r1,r2),1,2 )then A10:
min r1,
r2 >= min f
by A8, A3, XXREAL_0:def 9;
now per cases
( min_p f < len f or min_p f >= len f )
;
case
min_p f < len f
;
( min f = min r1,r2 & min_p f = IFEQ r1,(min r1,r2),1,2 )then
min_p f < 1
+ 1
by A1, FINSEQ_1:61;
then
min_p f <= 1
by NAT_1:13;
then A11:
min_p f = 1
by A6, XXREAL_0:1;
then
min f >= min r1,
r2
by A8, XXREAL_0:17;
then
min f = min r1,
r2
by A10, XXREAL_0:1;
hence
(
min f = min r1,
r2 &
min_p f = IFEQ r1,
(min r1,r2),1,2 )
by A8, A11, FUNCOP_1:def 8;
verum end; case
min_p f >= len f
;
( min f = min r1,r2 & min_p f = IFEQ r1,(min r1,r2),1,2 )then A12:
min_p f = 2
by A2, A9, XXREAL_0:1;
then
min f >= min r1,
r2
by A4, XXREAL_0:17;
then A13:
min f = min r1,
r2
by A10, XXREAL_0:1;
1
in dom f
by A2, FINSEQ_3:27;
then
r1 <> r2
by A2, A8, A4, A12, Def2;
hence
(
min f = min r1,
r2 &
min_p f = IFEQ r1,
(min r1,r2),1,2 )
by A4, A12, A13, FUNCOP_1:def 8;
verum end; end; end; hence
(
min f = min r1,
r2 &
min_p f = IFEQ r1,
(min r1,r2),1,2 )
;
verum end; suppose
r1 > r2
;
( min f = min r1,r2 & min_p f = IFEQ r1,(min r1,r2),1,2 )then A14:
min r1,
r2 >= min f
by A4, A7, XXREAL_0:def 9;
now per cases
( min_p f < len f or min_p f >= len f )
;
case
min_p f < len f
;
( min f = min r1,r2 & min_p f = IFEQ r1,(min r1,r2),1,2 )then
min_p f < 1
+ 1
by A1, FINSEQ_1:61;
then
min_p f <= 1
by NAT_1:13;
then A15:
min_p f = 1
by A6, XXREAL_0:1;
then
min f >= min r1,
r2
by A8, XXREAL_0:17;
then
min f = min r1,
r2
by A14, XXREAL_0:1;
hence
(
min f = min r1,
r2 &
min_p f = IFEQ r1,
(min r1,r2),1,2 )
by A8, A15, FUNCOP_1:def 8;
verum end; case
min_p f >= len f
;
( min f = min r1,r2 & min_p f = IFEQ r1,(min r1,r2),1,2 )then A16:
min_p f = 2
by A2, A9, XXREAL_0:1;
then
min f >= min r1,
r2
by A4, XXREAL_0:17;
then A17:
min f = min r1,
r2
by A14, XXREAL_0:1;
1
in dom f
by A2, FINSEQ_3:27;
then
r1 <> r2
by A2, A8, A4, A16, Def2;
hence
(
min f = min r1,
r2 &
min_p f = IFEQ r1,
(min r1,r2),1,2 )
by A4, A16, A17, FUNCOP_1:def 8;
verum end; end; end; hence
(
min f = min r1,
r2 &
min_p f = IFEQ r1,
(min r1,r2),1,2 )
;
verum end; end;