let f, g be FinSequence of (TOP-REAL 2); for p being Point of (TOP-REAL 2) st f . (len f) = g . 1 & p in L~ f & f is being_S-Seq & g is being_S-Seq & (L~ f) /\ (L~ g) = {(g . 1)} & p <> f . (len f) holds
(L_Cut (f,p)) ^ (mid (g,2,(len g))) is_S-Seq_joining p,g /. (len g)
let p be Point of (TOP-REAL 2); ( f . (len f) = g . 1 & p in L~ f & f is being_S-Seq & g is being_S-Seq & (L~ f) /\ (L~ g) = {(g . 1)} & p <> f . (len f) implies (L_Cut (f,p)) ^ (mid (g,2,(len g))) is_S-Seq_joining p,g /. (len g) )
assume that
A1:
f . (len f) = g . 1
and
A2:
p in L~ f
and
A3:
f is being_S-Seq
and
A4:
g is being_S-Seq
and
A5:
(L~ f) /\ (L~ g) = {(g . 1)}
and
A6:
p <> f . (len f)
; (L_Cut (f,p)) ^ (mid (g,2,(len g))) is_S-Seq_joining p,g /. (len g)
L_Cut (f,p) is_S-Seq_joining p,f /. (len f)
by A2, A3, A6, Th33;
then A7:
(L_Cut (f,p)) . (len (L_Cut (f,p))) = f /. (len f)
;
A8:
len g >= 2
by A4, TOPREAL1:def 8;
then A9:
1 <= len g
by XXREAL_0:2;
g /. 1 in LSeg ((g /. 1),(g /. (1 + 1)))
by RLTOPSP1:68;
then
g /. 1 in LSeg (g,1)
by A8, TOPREAL1:def 3;
then
g . 1 in LSeg (g,1)
by A9, FINSEQ_4:15;
then A10:
g . 1 in L~ g
by SPPOL_2:17;
L~ (L_Cut (f,p)) c= L~ f
by A2, Th42;
then A11:
(L~ (L_Cut (f,p))) /\ (L~ g) c= (L~ f) /\ (L~ g)
by XBOOLE_1:27;
len f >= 2
by A3, TOPREAL1:def 8;
then A12:
1 <= len f
by XXREAL_0:2;
A13:
L_Cut (f,p) is being_S-Seq
by A2, A3, A6, Th34;
then A14:
1 + 1 <= len (L_Cut (f,p))
by TOPREAL1:def 8;
then A15:
(1 + 1) - 1 <= (len (L_Cut (f,p))) - 1
by XREAL_1:9;
A16:
1 <= len (L_Cut (f,p))
by A14, XXREAL_0:2;
then
(L_Cut (f,p)) . 1 = (L_Cut (f,p)) /. 1
by FINSEQ_4:15;
then A17:
(L_Cut (f,p)) /. 1 = p
by A2, Th23;
A18:
((len (L_Cut (f,p))) -' 1) + 1 = len (L_Cut (f,p))
by A14, XREAL_1:235, XXREAL_0:2;
then
(L_Cut (f,p)) /. (len (L_Cut (f,p))) in LSeg (((L_Cut (f,p)) /. ((len (L_Cut (f,p))) -' 1)),((L_Cut (f,p)) /. (((len (L_Cut (f,p))) -' 1) + 1)))
by RLTOPSP1:68;
then
(L_Cut (f,p)) . (len (L_Cut (f,p))) in LSeg (((L_Cut (f,p)) /. ((len (L_Cut (f,p))) -' 1)),((L_Cut (f,p)) /. (((len (L_Cut (f,p))) -' 1) + 1)))
by A16, FINSEQ_4:15;
then
(L_Cut (f,p)) . (len (L_Cut (f,p))) in LSeg ((L_Cut (f,p)),((len (L_Cut (f,p))) -' 1))
by A15, A18, TOPREAL1:def 3;
then
f /. (len f) in L~ (L_Cut (f,p))
by A7, SPPOL_2:17;
then
f . (len f) in L~ (L_Cut (f,p))
by A12, FINSEQ_4:15;
then
g . 1 in (L~ (L_Cut (f,p))) /\ (L~ g)
by A1, A10, XBOOLE_0:def 4;
then
{(g . 1)} c= (L~ (L_Cut (f,p))) /\ (L~ g)
by ZFMISC_1:31;
then
(L~ (L_Cut (f,p))) /\ (L~ g) = {(g . 1)}
by A5, A11, XBOOLE_0:def 10;
hence
(L_Cut (f,p)) ^ (mid (g,2,(len g))) is_S-Seq_joining p,g /. (len g)
by A1, A4, A12, A13, A7, A17, Th39, FINSEQ_4:15; verum