let x0 be Real; 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; ( 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 that
A1:
f1 is_convergent_in x0
and
A2:
f2 is_convergent_in x0
; ( 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 A3:
0 < r
and
A4:
( ( (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 ) ) )
; lim (f1,x0) <= lim (f2,x0)
now lim (f1,x0) <= lim (f2,x0)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 A4;
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 ) )
;
lim (f1,x0) <= lim (f2,x0)defpred S1[
Nat,
Real]
means (
x0 - (1 / ($1 + 1)) < $2 & $2
< x0 & $2
in dom f1 );
consider s being
Real_Sequence such that A11:
for
n being
Element of
NAT holds
S1[
n,
s . n]
from FUNCT_2:sch 3(A6);
A12:
lim s = x0
by A11, Th6;
A13:
rng s c= (dom f1) \ {x0}
by A11, Th6;
A14:
s is
convergent
by A11, Th6;
x0 - r < x0
by A3, Lm1;
then consider k being
Nat such that A15:
for
n being
Nat st
k <= n holds
x0 - r < s . n
by A14, A12, LIMFUNC2:1;
A16:
lim (s ^\ k) = x0
by A14, A12, SEQ_4:20;
rng (s ^\ k) c= rng s
by VALUED_0:21;
then A17:
rng (s ^\ k) c= (dom f1) \ {x0}
by A13;
then A18:
lim (f1 /* (s ^\ k)) = lim (
f1,
x0)
by A1, A14, A16, Def4;
now for x being object st x in rng (s ^\ k) holds
x in (dom f1) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[)let x be
object ;
( x in rng (s ^\ k) implies x in (dom f1) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) )assume
x in rng (s ^\ k)
;
x in (dom f1) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[)then consider n being
Element of
NAT such that A19:
(s ^\ k) . n = x
by FUNCT_2:113;
A20:
n + k in NAT
by ORDINAL1:def 12;
s . (n + k) < x0
by A11, A20;
then A21:
(s ^\ k) . n < x0
by NAT_1:def 3;
x0 - r < s . (n + k)
by A15, NAT_1:12;
then
x0 - r < (s ^\ k) . n
by NAT_1:def 3;
then
(s ^\ k) . n in { g2 where g2 is Real : ( x0 - r < g2 & g2 < x0 ) }
by A21;
then
(s ^\ k) . n in ].(x0 - r),x0.[
by RCOMP_1:def 2;
then A22:
(s ^\ k) . n in ].(x0 - r),x0.[ \/ ].x0,(x0 + r).[
by XBOOLE_0:def 3;
s . (n + k) in dom f1
by A11, A20;
then
(s ^\ k) . n in dom f1
by NAT_1:def 3;
hence
x in (dom f1) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[)
by A19, A22, XBOOLE_0:def 4;
verum end; then A23:
rng (s ^\ k) c= (dom f1) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[)
;
then A24:
rng (s ^\ k) c= (dom f2) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[)
by A5;
A27:
rng (s ^\ k) c= dom f2
by A24, XBOOLE_1:18;
A28:
rng (s ^\ k) c= (dom f2) \ {x0}
then A30:
lim (f2 /* (s ^\ k)) = lim (
f2,
x0)
by A2, A14, A16, Def4;
A31:
f2 /* (s ^\ k) is
convergent
by A2, A14, A16, A28;
f1 /* (s ^\ k) is
convergent
by A1, A14, A16, A17;
hence
lim (
f1,
x0)
<= lim (
f2,
x0)
by A18, A31, A30, A25, SEQ_2:18;
verum end; suppose A32:
(
(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 ) )
;
lim (f1,x0) <= lim (f2,x0)defpred S1[
Element of
NAT ,
Real]
means (
x0 - (1 / ($1 + 1)) < $2 & $2
< x0 & $2
in dom f2 );
consider s being
Real_Sequence such that A38:
for
n being
Element of
NAT holds
S1[
n,
s . n]
from FUNCT_2:sch 3(A33);
A39:
lim s = x0
by A38, Th6;
A40:
rng s c= (dom f2) \ {x0}
by A38, Th6;
A41:
s is
convergent
by A38, Th6;
x0 - r < x0
by A3, Lm1;
then consider k being
Nat such that A42:
for
n being
Nat st
k <= n holds
x0 - r < s . n
by A41, A39, LIMFUNC2:1;
A43:
lim (s ^\ k) = x0
by A41, A39, SEQ_4:20;
rng (s ^\ k) c= rng s
by VALUED_0:21;
then A44:
rng (s ^\ k) c= (dom f2) \ {x0}
by A40;
then A45:
lim (f2 /* (s ^\ k)) = lim (
f2,
x0)
by A2, A41, A43, Def4;
A46:
now for x being object st x in rng (s ^\ k) holds
x in (dom f2) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[)let x be
object ;
( x in rng (s ^\ k) implies x in (dom f2) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[) )assume
x in rng (s ^\ k)
;
x in (dom f2) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[)then consider n being
Element of
NAT such that A47:
(s ^\ k) . n = x
by FUNCT_2:113;
A48:
n + k in NAT
by ORDINAL1:def 12;
s . (n + k) < x0
by A38, A48;
then A49:
(s ^\ k) . n < x0
by NAT_1:def 3;
x0 - r < s . (n + k)
by A42, NAT_1:12;
then
x0 - r < (s ^\ k) . n
by NAT_1:def 3;
then
(s ^\ k) . n in { g2 where g2 is Real : ( x0 - r < g2 & g2 < x0 ) }
by A49;
then
(s ^\ k) . n in ].(x0 - r),x0.[
by RCOMP_1:def 2;
then A50:
(s ^\ k) . n in ].(x0 - r),x0.[ \/ ].x0,(x0 + r).[
by XBOOLE_0:def 3;
s . (n + k) in dom f2
by A38, A48;
then
(s ^\ k) . n in dom f2
by NAT_1:def 3;
hence
x in (dom f2) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[)
by A47, A50, XBOOLE_0:def 4;
verum end; then A51:
rng (s ^\ k) c= (dom f2) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[)
;
then A52:
rng (s ^\ k) c= (dom f1) /\ (].(x0 - r),x0.[ \/ ].x0,(x0 + r).[)
by A32;
A55:
rng (s ^\ k) c= dom f1
by A52, XBOOLE_1:18;
A56:
rng (s ^\ k) c= (dom f1) \ {x0}
then A58:
lim (f1 /* (s ^\ k)) = lim (
f1,
x0)
by A1, A41, A43, Def4;
A59:
f1 /* (s ^\ k) is
convergent
by A1, A41, A43, A56;
f2 /* (s ^\ k) is
convergent
by A2, A41, A43, A44;
hence
lim (
f1,
x0)
<= lim (
f2,
x0)
by A45, A59, A58, A53, SEQ_2:18;
verum end; end; end;
hence
lim (f1,x0) <= lim (f2,x0)
; verum