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 (((1 / 2) * ((G * 1,j) + (G * 1,(j + 1)))) - |[1,0 ]|),p meets Int (cell G,0 ,j)
let p be Point of (TOP-REAL 2); for G being Go-board st 1 <= j & j + 1 <= width G holds
LSeg (((1 / 2) * ((G * 1,j) + (G * 1,(j + 1)))) - |[1,0 ]|),p meets Int (cell G,0 ,j)
let G be Go-board; ( 1 <= j & j + 1 <= width G implies LSeg (((1 / 2) * ((G * 1,j) + (G * 1,(j + 1)))) - |[1,0 ]|),p meets Int (cell G,0 ,j) )
assume A1:
( 1 <= j & j + 1 <= width G )
; LSeg (((1 / 2) * ((G * 1,j) + (G * 1,(j + 1)))) - |[1,0 ]|),p meets Int (cell G,0 ,j)
now take a =
((1 / 2) * ((G * 1,j) + (G * 1,(j + 1)))) - |[1,0 ]|;
( a in LSeg (((1 / 2) * ((G * 1,j) + (G * 1,(j + 1)))) - |[1,0 ]|),p & a in Int (cell G,0 ,j) )thus
a in LSeg (((1 / 2) * ((G * 1,j) + (G * 1,(j + 1)))) - |[1,0 ]|),
p
by RLTOPSP1:69;
a in Int (cell G,0 ,j)thus
a in Int (cell G,0 ,j)
by A1, Th38;
verum end;
hence
LSeg (((1 / 2) * ((G * 1,j) + (G * 1,(j + 1)))) - |[1,0 ]|),p meets Int (cell G,0 ,j)
by XBOOLE_0:3; verum