let x0 be Real; :: thesis: for f1, f2 being PartFunc of REAL ,REAL st f1 is_convergent_in x0 & f2 is_convergent_in x0 & ex r being Real st
( 0 < r & ( ( (dom f1) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) c= (dom f2) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) & ( for g being Real st g in (dom f1) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) holds
f1 . g <= f2 . g ) ) or ( (dom f2) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) c= (dom f1) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) & ( for g being Real st g in (dom f2) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) holds
f1 . g <= f2 . g ) ) ) ) holds
lim f1,x0 <= lim f2,x0
let f1, f2 be PartFunc of REAL ,REAL ; :: thesis: ( f1 is_convergent_in x0 & f2 is_convergent_in x0 & ex r being Real st
( 0 < r & ( ( (dom f1) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) c= (dom f2) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) & ( for g being Real st g in (dom f1) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) holds
f1 . g <= f2 . g ) ) or ( (dom f2) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) c= (dom f1) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) & ( for g being Real st g in (dom f2) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) holds
f1 . g <= f2 . g ) ) ) ) implies lim f1,x0 <= lim f2,x0 )
assume A1:
( f1 is_convergent_in x0 & f2 is_convergent_in x0 )
; :: thesis: ( for r being Real holds
( not 0 < r or ( not ( (dom f1) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) c= (dom f2) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) & ( for g being Real st g in (dom f1) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) holds
f1 . g <= f2 . g ) ) & not ( (dom f2) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) c= (dom f1) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) & ( for g being Real st g in (dom f2) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) holds
f1 . g <= f2 . g ) ) ) ) or lim f1,x0 <= lim f2,x0 )
given r being Real such that A2:
0 < r
and
A3:
( ( (dom f1) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) c= (dom f2) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) & ( for g being Real st g in (dom f1) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) holds
f1 . g <= f2 . g ) ) or ( (dom f2) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) c= (dom f1) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) & ( for g being Real st g in (dom f2) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) holds
f1 . g <= f2 . g ) ) )
; :: thesis: lim f1,x0 <= lim f2,x0
A4:
( lim f1,x0 = lim f1,x0 & lim f2,x0 = lim f2,x0 )
;
now per cases
( ( (dom f1) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) c= (dom f2) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) & ( for g being Real st g in (dom f1) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) holds
f1 . g <= f2 . g ) ) or ( (dom f2) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) c= (dom f1) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) & ( for g being Real st g in (dom f2) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) holds
f1 . g <= f2 . g ) ) )
by A3;
suppose A5:
(
(dom f1) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) c= (dom f2) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) & ( for
g being
Real st
g in (dom f1) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) holds
f1 . g <= f2 . g ) )
;
:: thesis: lim f1,x0 <= lim f2,x0defpred S1[
Element of
NAT ,
real number ]
means (
x0 - (1 / ($1 + 1)) < $2 & $2
< x0 & $2
in dom f1 );
consider s being
Real_Sequence such that A9:
for
n being
Element of
NAT holds
S1[
n,
s . n]
from FUNCT_2:sch 3(A6);
A10:
(
s is
convergent &
lim s = x0 &
rng s c= (dom f1) \ {x0} )
by A9, Th6;
x0 - r < x0
by A2, Lm1;
then consider k being
Element of
NAT such that A11:
for
n being
Element of
NAT st
k <= n holds
x0 - r < s . n
by A10, LIMFUNC2:1;
A12:
(
s ^\ k is
convergent &
lim (s ^\ k) = x0 )
by A10, SEQ_4:33;
rng (s ^\ k) c= rng s
by VALUED_0:21;
then A13:
rng (s ^\ k) c= (dom f1) \ {x0}
by A10, XBOOLE_1:1;
then A14:
(
f1 /* (s ^\ k) is
convergent &
lim (f1 /* (s ^\ k)) = lim f1,
x0 )
by A1, A4, A12, Def4;
now let x be
set ;
:: thesis: ( x in rng (s ^\ k) implies x in (dom f1) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) )assume
x in rng (s ^\ k)
;
:: thesis: x in (dom f1) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[)then consider n being
Element of
NAT such that A15:
(s ^\ k) . n = x
by FUNCT_2:190;
x0 - r < s . (n + k)
by A11, NAT_1:12;
then A16:
x0 - r < (s ^\ k) . n
by NAT_1:def 3;
(
s . (n + k) < x0 &
s . (n + k) in dom f1 )
by A9;
then A17:
(
(s ^\ k) . n < x0 &
(s ^\ k) . n in dom f1 )
by NAT_1:def 3;
then
(s ^\ k) . n in { g2 where g2 is Real : ( x0 - r < g2 & g2 < x0 ) }
by A16;
then
(s ^\ k) . n in ].(x0 - r),x0.[
by RCOMP_1:def 2;
then
(s ^\ k) . n in ].(x0 - r),x0.[ \/ ].x0,(x0 + r).[
by XBOOLE_0:def 3;
hence
x in (dom f1) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[)
by A15, A17, XBOOLE_0:def 4;
:: thesis: verum end; then A18:
rng (s ^\ k) c= (dom f1) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[)
by TARSKI:def 3;
then A19:
rng (s ^\ k) c= (dom f2) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[)
by A5, XBOOLE_1:1;
then A20:
rng (s ^\ k) c= dom f2
by XBOOLE_1:18;
rng (s ^\ k) c= (dom f2) \ {x0}
then A22:
(
f2 /* (s ^\ k) is
convergent &
lim (f2 /* (s ^\ k)) = lim f2,
x0 )
by A1, A4, A12, Def4;
hence
lim f1,
x0 <= lim f2,
x0
by A14, A22, SEQ_2:32;
:: thesis: verum end; suppose A23:
(
(dom f2) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) c= (dom f1) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) & ( for
g being
Real st
g in (dom f2) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) holds
f1 . g <= f2 . g ) )
;
:: thesis: lim f1,x0 <= lim f2,x0defpred S1[
Element of
NAT ,
real number ]
means (
x0 - (1 / ($1 + 1)) < $2 & $2
< x0 & $2
in dom f2 );
consider s being
Real_Sequence such that A27:
for
n being
Element of
NAT holds
S1[
n,
s . n]
from FUNCT_2:sch 3(A24);
A28:
(
s is
convergent &
lim s = x0 &
rng s c= (dom f2) \ {x0} )
by A27, Th6;
x0 - r < x0
by A2, Lm1;
then consider k being
Element of
NAT such that A29:
for
n being
Element of
NAT st
k <= n holds
x0 - r < s . n
by A28, LIMFUNC2:1;
A30:
(
s ^\ k is
convergent &
lim (s ^\ k) = x0 )
by A28, SEQ_4:33;
rng (s ^\ k) c= rng s
by VALUED_0:21;
then A31:
rng (s ^\ k) c= (dom f2) \ {x0}
by A28, XBOOLE_1:1;
then A32:
(
f2 /* (s ^\ k) is
convergent &
lim (f2 /* (s ^\ k)) = lim f2,
x0 )
by A1, A4, A30, Def4;
A33:
now let x be
set ;
:: thesis: ( x in rng (s ^\ k) implies x in (dom f2) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) )assume
x in rng (s ^\ k)
;
:: thesis: x in (dom f2) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[)then consider n being
Element of
NAT such that A34:
(s ^\ k) . n = x
by FUNCT_2:190;
x0 - r < s . (n + k)
by A29, NAT_1:12;
then A35:
x0 - r < (s ^\ k) . n
by NAT_1:def 3;
(
s . (n + k) < x0 &
s . (n + k) in dom f2 )
by A27;
then A36:
(
(s ^\ k) . n < x0 &
(s ^\ k) . n in dom f2 )
by NAT_1:def 3;
then
(s ^\ k) . n in { g2 where g2 is Real : ( x0 - r < g2 & g2 < x0 ) }
by A35;
then
(s ^\ k) . n in ].(x0 - r),x0.[
by RCOMP_1:def 2;
then
(s ^\ k) . n in ].(x0 - r),x0.[ \/ ].x0,(x0 + r).[
by XBOOLE_0:def 3;
hence
x in (dom f2) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[)
by A34, A36, XBOOLE_0:def 4;
:: thesis: verum end; then A37:
rng (s ^\ k) c= (dom f2) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[)
by TARSKI:def 3;
then A38:
rng (s ^\ k) c= (dom f1) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[)
by A23, XBOOLE_1:1;
then A39:
rng (s ^\ k) c= dom f1
by XBOOLE_1:18;
rng (s ^\ k) c= (dom f1) \ {x0}
then A41:
(
f1 /* (s ^\ k) is
convergent &
lim (f1 /* (s ^\ k)) = lim f1,
x0 )
by A1, A4, A30, Def4;
hence
lim f1,
x0 <= lim f2,
x0
by A32, A41, SEQ_2:32;
:: thesis: verum end; end; end;
hence
lim f1,x0 <= lim f2,x0
; :: thesis: verum