let x0 be Real; :: thesis: for f1, f2 being PartFunc of REAL ,REAL st f1 is_right_divergent_to+infty_in x0 & ( for r being Real st x0 < r holds
ex g being Real st
( g < r & x0 < g & g in dom (f1 (#) f2) ) ) & ex r, r1 being Real st
( 0 < r & 0 < r1 & ( for g being Real st g in (dom f2) /\ ].x0,(x0 + r).[ holds
r1 <= f2 . g ) ) holds
f1 (#) f2 is_right_divergent_to+infty_in x0
let f1, f2 be PartFunc of REAL ,REAL ; :: thesis: ( f1 is_right_divergent_to+infty_in x0 & ( for r being Real st x0 < r holds
ex g being Real st
( g < r & x0 < g & g in dom (f1 (#) f2) ) ) & ex r, r1 being Real st
( 0 < r & 0 < r1 & ( for g being Real st g in (dom f2) /\ ].x0,(x0 + r).[ holds
r1 <= f2 . g ) ) implies f1 (#) f2 is_right_divergent_to+infty_in x0 )
assume A1:
( f1 is_right_divergent_to+infty_in x0 & ( for r being Real st x0 < r holds
ex g being Real st
( g < r & x0 < g & g in dom (f1 (#) f2) ) ) )
; :: thesis: ( for r, r1 being Real holds
( not 0 < r or not 0 < r1 or ex g being Real st
( g in (dom f2) /\ ].x0,(x0 + r).[ & not r1 <= f2 . g ) ) or f1 (#) f2 is_right_divergent_to+infty_in x0 )
given r, t being Real such that A2:
( 0 < r & 0 < t & ( for g being Real st g in (dom f2) /\ ].x0,(x0 + r).[ holds
t <= f2 . g ) )
; :: thesis: f1 (#) f2 is_right_divergent_to+infty_in x0
now let seq be
Real_Sequence;
:: thesis: ( seq is convergent & lim seq = x0 & rng seq c= (dom (f1 (#) f2)) /\ (right_open_halfline x0) implies (f1 (#) f2) /* seq is divergent_to+infty )assume A3:
(
seq is
convergent &
lim seq = x0 &
rng seq c= (dom (f1 (#) f2)) /\ (right_open_halfline x0) )
;
:: thesis: (f1 (#) f2) /* seq is divergent_to+infty
x0 < x0 + r
by A2, Lm1;
then consider k being
Element of
NAT such that A4:
for
n being
Element of
NAT st
k <= n holds
seq . n < x0 + r
by A3, Th2;
A5:
(
seq ^\ k is
convergent &
lim (seq ^\ k) = x0 )
by A3, SEQ_4:33;
rng (seq ^\ k) c= rng seq
by VALUED_0:21;
then
rng (seq ^\ k) c= (dom (f1 (#) f2)) /\ (right_open_halfline x0)
by A3, XBOOLE_1:1;
then A6:
(
rng (seq ^\ k) c= dom (f1 (#) f2) &
rng (seq ^\ k) c= right_open_halfline x0 &
dom (f1 (#) f2) = (dom f1) /\ (dom f2) &
rng (seq ^\ k) c= dom f1 &
rng (seq ^\ k) c= dom f2 &
rng (seq ^\ k) c= (dom f1) /\ (right_open_halfline x0) )
by Lm2;
then A7:
f1 /* (seq ^\ k) is
divergent_to+infty
by A1, A5, Def5;
A8:
rng seq c= dom (f1 (#) f2)
by A3, Lm2;
then A11:
(f1 /* (seq ^\ k)) (#) (f2 /* (seq ^\ k)) is
divergent_to+infty
by A7, LIMFUNC1:49;
(f1 /* (seq ^\ k)) (#) (f2 /* (seq ^\ k)) =
(f1 (#) f2) /* (seq ^\ k)
by A6, RFUNCT_2:23
.=
((f1 (#) f2) /* seq) ^\ k
by A8, VALUED_0:27
;
hence
(f1 (#) f2) /* seq is
divergent_to+infty
by A11, LIMFUNC1:34;
:: thesis: verum end;
hence
f1 (#) f2 is_right_divergent_to+infty_in x0
by A1, Def5; :: thesis: verum