let n be Element of NAT ; for C being connected compact non horizontal non vertical Subset of (TOP-REAL 2)
for x, p being Point of (TOP-REAL 2) st x in W-most C & p in (west_halfline x) /\ (L~ (Cage C,n)) holds
p `1 = W-bound (L~ (Cage C,n))
let C be connected compact non horizontal non vertical Subset of (TOP-REAL 2); for x, p being Point of (TOP-REAL 2) st x in W-most C & p in (west_halfline x) /\ (L~ (Cage C,n)) holds
p `1 = W-bound (L~ (Cage C,n))
let x, p be Point of (TOP-REAL 2); ( x in W-most C & p in (west_halfline x) /\ (L~ (Cage C,n)) implies p `1 = W-bound (L~ (Cage C,n)) )
set G = Gauge C,n;
set f = Cage C,n;
A1:
Cage C,n is_sequence_on Gauge C,n
by JORDAN9:def 1;
assume A2:
x in W-most C
; ( not p in (west_halfline x) /\ (L~ (Cage C,n)) or p `1 = W-bound (L~ (Cage C,n)) )
then A3:
x in C
by XBOOLE_0:def 4;
A4:
len (Gauge C,n) = width (Gauge C,n)
by JORDAN8:def 1;
assume A5:
p in (west_halfline x) /\ (L~ (Cage C,n))
; p `1 = W-bound (L~ (Cage C,n))
then
p in L~ (Cage C,n)
by XBOOLE_0:def 4;
then consider i being Element of NAT such that
A6:
1 <= i
and
A7:
i + 1 <= len (Cage C,n)
and
A8:
p in LSeg (Cage C,n),i
by SPPOL_2:13;
A9:
LSeg (Cage C,n),i = LSeg ((Cage C,n) /. i),((Cage C,n) /. (i + 1))
by A6, A7, TOPREAL1:def 5;
A10:
i < len (Cage C,n)
by A7, NAT_1:13;
then
i in Seg (len (Cage C,n))
by A6, FINSEQ_1:3;
then
i in dom (Cage C,n)
by FINSEQ_1:def 3;
then consider i1, i2 being Element of NAT such that
A11:
[i1,i2] in Indices (Gauge C,n)
and
A12:
(Cage C,n) /. i = (Gauge C,n) * i1,i2
by A1, GOBOARD1:def 11;
A13:
( 1 <= i2 & i2 <= width (Gauge C,n) )
by A11, MATRIX_1:39;
p in west_halfline x
by A5, XBOOLE_0:def 4;
then
LSeg (Cage C,n),i is vertical
by A2, A6, A8, A10, Th102;
then
((Cage C,n) /. i) `1 = ((Cage C,n) /. (i + 1)) `1
by A9, SPPOL_1:37;
then A14:
p `1 = ((Cage C,n) /. i) `1
by A8, A9, GOBOARD7:5;
A15:
i1 <= len (Gauge C,n)
by A11, MATRIX_1:39;
A16:
1 <= i1
by A11, MATRIX_1:39;
x `1 =
(W-min C) `1
by A2, PSCOMP_1:88
.=
W-bound C
by EUCLID:56
.=
((Gauge C,n) * 2,i2) `1
by A4, A13, JORDAN8:14
;
then
i1 < 1 + 1
by A3, A5, A12, A13, A15, A14, Th98, SPRECT_3:25;
then
i1 <= 1
by NAT_1:13;
then
i1 = 1
by A16, XXREAL_0:1;
then
(Cage C,n) /. i in W-most (L~ (Cage C,n))
by A6, A10, A12, A13, Th80;
hence
p `1 = W-bound (L~ (Cage C,n))
by A14, Th14; verum