let C be Simple_closed_curve; :: thesis: W-min C in North_Arc C
A1:
North_Arc C = Lim_inf (Upper_Appr C)
by JORDAN19:def 3;
reconsider w = W-min C as Point of (Euclid 2) by EUCLID:71;
for r being real number st r > 0 holds
ex k being Element of NAT st
for m being Element of NAT st m > k holds
(Upper_Appr C) . m meets Ball w,r
proof
let r be
real number ;
:: thesis: ( r > 0 implies ex k being Element of NAT st
for m being Element of NAT st m > k holds
(Upper_Appr C) . m meets Ball w,r )
assume
r > 0
;
:: thesis: ex k being Element of NAT st
for m being Element of NAT st m > k holds
(Upper_Appr C) . m meets Ball w,r
then
r / 2
> 0
by XREAL_1:217;
then consider k being
Element of
NAT such that
1
< k
and A2:
dist ((Gauge C,k) * 1,1),
((Gauge C,k) * 1,2) < r / 2
and A3:
dist ((Gauge C,k) * 1,1),
((Gauge C,k) * 2,1) < r / 2
by GOBRD14:21;
take
k
;
:: thesis: for m being Element of NAT st m > k holds
(Upper_Appr C) . m meets Ball w,r
let m be
Element of
NAT ;
:: thesis: ( m > k implies (Upper_Appr C) . m meets Ball w,r )
assume A4:
m > k
;
:: thesis: (Upper_Appr C) . m meets Ball w,r
reconsider p =
W-min (L~ (Cage C,m)) as
Point of
(Euclid 2) by EUCLID:71;
A5:
(Upper_Appr C) . m = Upper_Arc (L~ (Cage C,m))
by JORDAN19:def 1;
A6:
W-min (L~ (Cage C,m)) in Upper_Arc (L~ (Cage C,m))
by JORDAN7:1;
A7:
W-min (L~ (Cage C,m)) in rng (Cage C,m)
by SPRECT_2:47;
A8:
1
+ 1
<= len (Cage C,m)
by GOBOARD7:36, XXREAL_0:2;
A9:
W-min (L~ (Cage C,m)) = (Rotate (Cage C,m),(W-min (L~ (Cage C,m)))) /. 1
by A7, FINSEQ_6:98;
A10:
1
+ 1
<= len (Rotate (Cage C,m),(W-min (L~ (Cage C,m))))
by A8, REVROT_1:14;
then A11:
(Rotate (Cage C,m),(W-min (L~ (Cage C,m)))) /. 1
in LSeg (Rotate (Cage C,m),(W-min (L~ (Cage C,m)))),1
by TOPREAL1:27;
(left_cell (Rotate (Cage C,m),(W-min (L~ (Cage C,m)))),1) /\ (right_cell (Rotate (Cage C,m),(W-min (L~ (Cage C,m)))),1) = LSeg (Rotate (Cage C,m),(W-min (L~ (Cage C,m)))),1
by A10, GOBOARD5:32;
then A12:
W-min (L~ (Cage C,m)) in right_cell (Rotate (Cage C,m),(W-min (L~ (Cage C,m)))),1
by A9, A11, XBOOLE_0:def 4;
A13:
W-min C in right_cell (Rotate (Cage C,m),(W-min (L~ (Cage C,m)))),1
by JORDAN1I:8;
A14:
right_cell (Rotate (Cage C,m),(W-min (L~ (Cage C,m)))),1 =
right_cell (Rotate (Cage C,m),(W-min (L~ (Cage C,m)))),1,
(GoB (Rotate (Cage C,m),(W-min (L~ (Cage C,m)))))
by A10, JORDAN1H:29
.=
right_cell (Rotate (Cage C,m),(W-min (L~ (Cage C,m)))),1,
(GoB (Cage C,m))
by REVROT_1:28
.=
right_cell (Rotate (Cage C,m),(W-min (L~ (Cage C,m)))),1,
(Gauge C,m)
by JORDAN1H:52
;
Cage C,
m is_sequence_on Gauge C,
m
by JORDAN9:def 1;
then A15:
Rotate (Cage C,m),
(W-min (L~ (Cage C,m))) is_sequence_on Gauge C,
m
by REVROT_1:34;
(Rotate (Cage C,m),(W-min (L~ (Cage C,m)))) /. 1
= W-min (L~ (Rotate (Cage C,m),(W-min (L~ (Cage C,m)))))
by A9, REVROT_1:33;
then consider i,
j being
Element of
NAT such that A16:
(
[i,j] in Indices (Gauge C,m) &
[i,(j + 1)] in Indices (Gauge C,m) )
and A17:
(
(Rotate (Cage C,m),(W-min (L~ (Cage C,m)))) /. 1
= (Gauge C,m) * i,
j &
(Rotate (Cage C,m),(W-min (L~ (Cage C,m)))) /. (1 + 1) = (Gauge C,m) * i,
(j + 1) )
by A10, A15, JORDAN1I:23;
A18:
right_cell (Rotate (Cage C,m),(W-min (L~ (Cage C,m)))),1
= cell (Gauge C,m),
i,
j
by A10, A14, A15, A16, A17, GOBRD13:23;
A19:
( 1
<= i & 1
<= j &
j + 1
<= width (Gauge C,m) )
by A16, MATRIX_1:39;
A20:
1
<= i + 1
by NAT_1:11;
A21:
j <= width (Gauge C,m)
by A16, MATRIX_1:39;
i < len (Gauge C,m)
by A10, A15, A16, A17, JORDAN1I:16;
then A22:
i + 1
<= len (Gauge C,m)
by NAT_1:13;
then A23:
[(i + 1),j] in Indices (Gauge C,m)
by A19, A20, A21, MATRIX_1:37;
(
((Gauge C,m) * i,j) `1 <= (W-min C) `1 &
(W-min C) `1 <= ((Gauge C,m) * (i + 1),j) `1 &
((Gauge C,m) * i,j) `2 <= (W-min C) `2 &
(W-min C) `2 <= ((Gauge C,m) * i,(j + 1)) `2 &
((Gauge C,m) * i,j) `1 <= (W-min (L~ (Cage C,m))) `1 &
(W-min (L~ (Cage C,m))) `1 <= ((Gauge C,m) * (i + 1),j) `1 &
((Gauge C,m) * i,j) `2 <= (W-min (L~ (Cage C,m))) `2 &
(W-min (L~ (Cage C,m))) `2 <= ((Gauge C,m) * i,(j + 1)) `2 )
by A12, A13, A18, A19, A22, JORDAN9:19;
then A24:
dist (W-min C),
(W-min (L~ (Cage C,m))) <= ((((Gauge C,m) * (i + 1),j) `1 ) - (((Gauge C,m) * i,j) `1 )) + ((((Gauge C,m) * i,(j + 1)) `2 ) - (((Gauge C,m) * i,j) `2 ))
by TOPREAL6:104;
A25:
[1,(1 + 1)] in Indices (Gauge C,m)
by Th6;
[(1 + 1),1] in Indices (Gauge C,m)
by Th7;
then A26:
dist ((Gauge C,m) * 1,1),
((Gauge C,m) * (1 + 1),1) = ((E-bound C) - (W-bound C)) / (2 |^ m)
by Th5, GOBRD14:20;
A27:
dist ((Gauge C,m) * 1,1),
((Gauge C,m) * 1,(1 + 1)) = ((N-bound C) - (S-bound C)) / (2 |^ m)
by A25, Th5, GOBRD14:19;
dist ((Gauge C,m) * 1,1),
((Gauge C,m) * 1,2) < dist ((Gauge C,k) * 1,1),
((Gauge C,k) * 1,2)
by A4, Th9;
then A28:
dist ((Gauge C,m) * 1,1),
((Gauge C,m) * 1,2) < r / 2
by A2, XXREAL_0:2;
dist ((Gauge C,m) * 1,1),
((Gauge C,m) * 2,1) < dist ((Gauge C,k) * 1,1),
((Gauge C,k) * 2,1)
by A4, Th11;
then A29:
dist ((Gauge C,m) * 1,1),
((Gauge C,m) * 2,1) < r / 2
by A3, XXREAL_0:2;
dist ((Gauge C,m) * 1,1),
((Gauge C,m) * 1,(1 + 1)) = dist ((Gauge C,m) * i,j),
((Gauge C,m) * i,(j + 1))
by A16, A27, GOBRD14:19;
then A30:
(((Gauge C,m) * i,(j + 1)) `2 ) - (((Gauge C,m) * i,j) `2 ) < r / 2
by A16, A28, GOBRD14:16;
dist ((Gauge C,m) * 1,1),
((Gauge C,m) * (1 + 1),1) = dist ((Gauge C,m) * i,j),
((Gauge C,m) * (i + 1),j)
by A16, A23, A26, GOBRD14:20;
then
(((Gauge C,m) * (i + 1),j) `1 ) - (((Gauge C,m) * i,j) `1 ) < r / 2
by A16, A23, A29, GOBRD14:15;
then
((((Gauge C,m) * (i + 1),j) `1 ) - (((Gauge C,m) * i,j) `1 )) + ((((Gauge C,m) * i,(j + 1)) `2 ) - (((Gauge C,m) * i,j) `2 )) < (r / 2) + (r / 2)
by A30, XREAL_1:10;
then
dist (W-min C),
(W-min (L~ (Cage C,m))) < r
by A24, XXREAL_0:2;
then
dist w,
p < r
by TOPREAL6:def 1;
then
p in Ball w,
r
by METRIC_1:12;
hence
(Upper_Appr C) . m meets Ball w,
r
by A5, A6, XBOOLE_0:3;
:: thesis: verum
end;
hence
W-min C in North_Arc C
by A1, KURATO_2:48; :: thesis: verum