let j be Element of NAT ; for p being Point of (TOP-REAL 2)
for G being Go-board st 1 <= j & j + 1 <= width G holds
LSeg p,(((1 / 2) * ((G * (len G),j) + (G * (len G),(j + 1)))) + |[1,0 ]|) meets Int (cell G,(len G),j)
let p be Point of (TOP-REAL 2); for G being Go-board st 1 <= j & j + 1 <= width G holds
LSeg p,(((1 / 2) * ((G * (len G),j) + (G * (len G),(j + 1)))) + |[1,0 ]|) meets Int (cell G,(len G),j)
let G be Go-board; ( 1 <= j & j + 1 <= width G implies LSeg p,(((1 / 2) * ((G * (len G),j) + (G * (len G),(j + 1)))) + |[1,0 ]|) meets Int (cell G,(len G),j) )
assume A1:
( 1 <= j & j + 1 <= width G )
; LSeg p,(((1 / 2) * ((G * (len G),j) + (G * (len G),(j + 1)))) + |[1,0 ]|) meets Int (cell G,(len G),j)
now take a =
((1 / 2) * ((G * (len G),j) + (G * (len G),(j + 1)))) + |[1,0 ]|;
( a in LSeg p,(((1 / 2) * ((G * (len G),j) + (G * (len G),(j + 1)))) + |[1,0 ]|) & a in Int (cell G,(len G),j) )thus
a in LSeg p,
(((1 / 2) * ((G * (len G),j) + (G * (len G),(j + 1)))) + |[1,0 ]|)
by RLTOPSP1:69;
a in Int (cell G,(len G),j)thus
a in Int (cell G,(len G),j)
by A1, Th37;
verum end;
hence
LSeg p,(((1 / 2) * ((G * (len G),j) + (G * (len G),(j + 1)))) + |[1,0 ]|) meets Int (cell G,(len G),j)
by XBOOLE_0:3; verum