let i, j be Element of NAT ; :: thesis: for p being Point of (TOP-REAL 2)
for G being Go-board st 1 <= i & i + 1 <= len G & 1 <= j & j + 1 <= width G holds
LSeg ((1 / 2) * ((G * i,j) + (G * (i + 1),(j + 1)))),p meets Int (cell G,i,j)
let p be Point of (TOP-REAL 2); :: thesis: for G being Go-board st 1 <= i & i + 1 <= len G & 1 <= j & j + 1 <= width G holds
LSeg ((1 / 2) * ((G * i,j) + (G * (i + 1),(j + 1)))),p meets Int (cell G,i,j)
let G be Go-board; :: thesis: ( 1 <= i & i + 1 <= len G & 1 <= j & j + 1 <= width G implies LSeg ((1 / 2) * ((G * i,j) + (G * (i + 1),(j + 1)))),p meets Int (cell G,i,j) )
assume that
A1:
( 1 <= i & i + 1 <= len G )
and
A2:
( 1 <= j & j + 1 <= width G )
; :: thesis: LSeg ((1 / 2) * ((G * i,j) + (G * (i + 1),(j + 1)))),p meets Int (cell G,i,j)
now take a =
(1 / 2) * ((G * i,j) + (G * (i + 1),(j + 1)));
:: thesis: ( a in LSeg ((1 / 2) * ((G * i,j) + (G * (i + 1),(j + 1)))),p & a in Int (cell G,i,j) )thus
a in LSeg ((1 / 2) * ((G * i,j) + (G * (i + 1),(j + 1)))),
p
by RLTOPSP1:69;
:: thesis: a in Int (cell G,i,j)thus
a in Int (cell G,i,j)
by A1, A2, Th34;
:: thesis: verum end;
hence
LSeg ((1 / 2) * ((G * i,j) + (G * (i + 1),(j + 1)))),p meets Int (cell G,i,j)
by XBOOLE_0:3; :: thesis: verum