let C be connected compact non horizontal non vertical Subset of (TOP-REAL 2); :: thesis: for i, n, j being Element of NAT st i <= len (Gauge C,n) & j <= width (Gauge C,n) & cell (Gauge C,n),i,j c= BDD C holds
i > 1
let i, n, j be Element of NAT ; :: thesis: ( i <= len (Gauge C,n) & j <= width (Gauge C,n) & cell (Gauge C,n),i,j c= BDD C implies i > 1 )
assume that
A1:
i <= len (Gauge C,n)
and
A2:
j <= width (Gauge C,n)
and
A3:
cell (Gauge C,n),i,j c= BDD C
and
A4:
i <= 1
; :: thesis: contradiction
per cases
( i = 0 or i = 1 )
by A4, NAT_1:26;
suppose A5:
i = 1
;
:: thesis: contradictionA6:
len (Gauge C,n) <> 0
by GOBOARD1:def 5;
then A7:
0 + 1
<= len (Gauge C,n)
by NAT_1:14;
then A8:
not
cell (Gauge C,n),1,
j is
empty
by A2, JORDAN1A:45;
A9:
cell (Gauge C,n),
0 ,
j c= UBD C
by A2, Th38;
A10:
j < width (Gauge C,n)
by A1, A2, A3, Lm6, XXREAL_0:1;
A11:
0 < len (Gauge C,n)
by A6;
j <> 0
by A1, A3, Lm4;
then
(cell (Gauge C,n),0 ,j) /\ (cell (Gauge C,n),(0 + 1),j) = LSeg ((Gauge C,n) * (0 + 1),j),
((Gauge C,n) * (0 + 1),(j + 1))
by A10, A11, GOBOARD5:26, NAT_1:14;
then A12:
cell (Gauge C,n),
0 ,
j meets cell (Gauge C,n),
(0 + 1),
j
by XBOOLE_0:def 7;
UBD C is_outside_component_of C
by JORDAN2C:73, JORDAN2C:76;
then A13:
UBD C is_a_component_of C `
by JORDAN2C:def 4;
BDD C c= C `
by JORDAN2C:29;
then
cell (Gauge C,n),1,
j c= C `
by A3, A5, XBOOLE_1:1;
then
cell (Gauge C,n),1,
j c= UBD C
by A2, A7, A9, A12, A13, GOBOARD9:6, JORDAN1A:46;
hence
contradiction
by A3, A5, A8, JORDAN2C:28, XBOOLE_1:68;
:: thesis: verum end; end;