let C be non empty compact non horizontal non vertical Subset of (TOP-REAL 2); for n being Nat ex i being Element of NAT st
( 1 <= i & i + 1 <= len (Gauge C,n) & N-min C in cell (Gauge C,n),i,((width (Gauge C,n)) -' 1) & N-min C <> (Gauge C,n) * i,((width (Gauge C,n)) -' 1) )
let n be Nat; ex i being Element of NAT st
( 1 <= i & i + 1 <= len (Gauge C,n) & N-min C in cell (Gauge C,n),i,((width (Gauge C,n)) -' 1) & N-min C <> (Gauge C,n) * i,((width (Gauge C,n)) -' 1) )
set G = Gauge C,n;
defpred S1[ Nat] means ( 1 <= $1 & $1 < len (Gauge C,n) & ((Gauge C,n) * $1,((width (Gauge C,n)) -' 1)) `1 < (N-min C) `1 );
A1:
for k being Nat st S1[k] holds
k <= len (Gauge C,n)
;
A2:
len (Gauge C,n) = width (Gauge C,n)
by JORDAN8:def 1;
(NW-corner C) `1 <= (N-min C) `1
by PSCOMP_1:97;
then A3:
W-bound C <= (N-min C) `1
by EUCLID:56;
A4:
len (Gauge C,n) >= 4
by JORDAN8:13;
then A5:
( (len (Gauge C,n)) -' 1 <= len (Gauge C,n) & 2 <= len (Gauge C,n) )
by NAT_D:35, XXREAL_0:2;
A6:
1 < len (Gauge C,n)
by A4, XXREAL_0:2;
then A7:
1 <= (len (Gauge C,n)) -' 1
by NAT_D:49;
A8:
( n in NAT & len (Gauge C,n) = width (Gauge C,n) )
by JORDAN8:def 1, ORDINAL1:def 13;
then
((Gauge C,n) * 2,((width (Gauge C,n)) -' 1)) `1 = W-bound C
by A7, JORDAN8:14, NAT_D:35;
then
((Gauge C,n) * 1,((width (Gauge C,n)) -' 1)) `1 < W-bound C
by A2, A7, A5, GOBOARD5:4;
then
((Gauge C,n) * 1,((width (Gauge C,n)) -' 1)) `1 < (N-min C) `1
by A3, XXREAL_0:2;
then A9:
ex k being Nat st S1[k]
by A6;
ex i being Nat st
( S1[i] & ( for n being Nat st S1[n] holds
n <= i ) )
from NAT_1:sch 6(A1, A9);
then consider i being Nat such that
A10:
1 <= i
and
A11:
i < len (Gauge C,n)
and
A12:
((Gauge C,n) * i,((width (Gauge C,n)) -' 1)) `1 < (N-min C) `1
and
A13:
for n being Nat st S1[n] holds
n <= i
;
reconsider i = i as Element of NAT by ORDINAL1:def 13;
A14:
( 1 <= i + 1 & i < i + 1 )
by NAT_1:12, NAT_1:13;
A15:
(N-min C) `2 = N-bound C
by EUCLID:56;
A16:
i + 1 <= len (Gauge C,n)
by A11, NAT_1:13;
then A17:
(N-min C) `2 = ((Gauge C,n) * (i + 1),((width (Gauge C,n)) -' 1)) `2
by A8, A15, JORDAN8:17, NAT_1:12;
now assume
i + 1
= len (Gauge C,n)
;
contradictionthen
(len (Gauge C,n)) -' 1
= i
by NAT_D:34;
then A18:
((Gauge C,n) * i,((width (Gauge C,n)) -' 1)) `1 = E-bound C
by A8, A7, JORDAN8:15, NAT_D:35;
(NE-corner C) `1 >= (N-min C) `1
by PSCOMP_1:97;
hence
contradiction
by A12, A18, EUCLID:56;
verum end;
then
i + 1 < len (Gauge C,n)
by A16, XXREAL_0:1;
then A19:
(N-min C) `1 <= ((Gauge C,n) * (i + 1),((width (Gauge C,n)) -' 1)) `1
by A13, A14;
((Gauge C,n) * i,((width (Gauge C,n)) -' 1)) `2 = (N-min C) `2
by A8, A10, A11, A15, JORDAN8:17;
then A20:
N-min C in LSeg ((Gauge C,n) * i,((width (Gauge C,n)) -' 1)),((Gauge C,n) * (i + 1),((width (Gauge C,n)) -' 1))
by A12, A17, A19, GOBOARD7:9;
take
i
; ( 1 <= i & i + 1 <= len (Gauge C,n) & N-min C in cell (Gauge C,n),i,((width (Gauge C,n)) -' 1) & N-min C <> (Gauge C,n) * i,((width (Gauge C,n)) -' 1) )
thus
( 1 <= i & i + 1 <= len (Gauge C,n) )
by A10, A11, NAT_1:13; ( N-min C in cell (Gauge C,n),i,((width (Gauge C,n)) -' 1) & N-min C <> (Gauge C,n) * i,((width (Gauge C,n)) -' 1) )
LSeg ((Gauge C,n) * i,((width (Gauge C,n)) -' 1)),((Gauge C,n) * (i + 1),((width (Gauge C,n)) -' 1)) c= cell (Gauge C,n),i,((width (Gauge C,n)) -' 1)
by A2, A7, A10, A11, GOBOARD5:23, NAT_D:35;
hence
N-min C in cell (Gauge C,n),i,((width (Gauge C,n)) -' 1)
by A20; N-min C <> (Gauge C,n) * i,((width (Gauge C,n)) -' 1)
thus
N-min C <> (Gauge C,n) * i,((width (Gauge C,n)) -' 1)
by A12; verum