let i, n be Element of NAT ; for C being compact non horizontal non vertical Subset of (TOP-REAL 2) st i <= len (Gauge C,n) holds
cell (Gauge C,n),i,0 c= UBD C
let C be compact non horizontal non vertical Subset of (TOP-REAL 2); ( i <= len (Gauge C,n) implies cell (Gauge C,n),i,0 c= UBD C )
A1:
not C ` is empty
by JORDAN2C:74;
assume A2:
i <= len (Gauge C,n)
; cell (Gauge C,n),i,0 c= UBD C
then
cell (Gauge C,n),i,0 misses C
by JORDAN8:20;
then A3:
cell (Gauge C,n),i,0 c= C `
by SUBSET_1:43;
0 <= width (Gauge C,n)
;
then
( cell (Gauge C,n),i,0 is connected & not cell (Gauge C,n),i,0 is empty )
by A2, Th45, Th46;
then consider W being Subset of (TOP-REAL 2) such that
A4:
W is_a_component_of C `
and
A5:
cell (Gauge C,n),i,0 c= W
by A3, A1, GOBOARD9:5;
not W is Bounded
by A2, A5, Th47, JORDAN2C:16;
then
W is_outside_component_of C
by A4, JORDAN2C:def 4;
then
W c= UBD C
by JORDAN2C:27;
hence
cell (Gauge C,n),i,0 c= UBD C
by A5, XBOOLE_1:1; verum