let C be Simple_closed_curve; for S being Segmentation of C
for i, j being Element of NAT st 1 <= i & i < j & j < len S & not i,j are_adjacent1 holds
Segm S,i misses Segm S,j
let S be Segmentation of C; for i, j being Element of NAT st 1 <= i & i < j & j < len S & not i,j are_adjacent1 holds
Segm S,i misses Segm S,j
let i, j be Element of NAT ; ( 1 <= i & i < j & j < len S & not i,j are_adjacent1 implies Segm S,i misses Segm S,j )
assume that
A1:
1 <= i
and
A2:
i < j
and
A3:
j < len S
and
A4:
not i,j are_adjacent1
; Segm S,i misses Segm S,j
i < len S
by A2, A3, XXREAL_0:2;
then A5:
Segm S,i = Segment (S /. i),(S /. (i + 1)),C
by A1, Def4;
1 < j
by A1, A2, XXREAL_0:2;
then
Segm S,j = Segment (S /. j),(S /. (j + 1)),C
by A3, Def4;
hence
Segm S,i misses Segm S,j
by A1, A2, A3, A4, A5, Def3; verum