let i be Element of NAT ; for p being Point of (TOP-REAL 2)
for G being Go-board st 1 <= i & i + 1 <= len G holds
LSeg (((1 / 2) * ((G * i,1) + (G * (i + 1),1))) - |[0 ,1]|),p meets Int (cell G,i,0 )
let p be Point of (TOP-REAL 2); for G being Go-board st 1 <= i & i + 1 <= len G holds
LSeg (((1 / 2) * ((G * i,1) + (G * (i + 1),1))) - |[0 ,1]|),p meets Int (cell G,i,0 )
let G be Go-board; ( 1 <= i & i + 1 <= len G implies LSeg (((1 / 2) * ((G * i,1) + (G * (i + 1),1))) - |[0 ,1]|),p meets Int (cell G,i,0 ) )
assume A1:
( 1 <= i & i + 1 <= len G )
; LSeg (((1 / 2) * ((G * i,1) + (G * (i + 1),1))) - |[0 ,1]|),p meets Int (cell G,i,0 )
now take a =
((1 / 2) * ((G * i,1) + (G * (i + 1),1))) - |[0 ,1]|;
( a in LSeg (((1 / 2) * ((G * i,1) + (G * (i + 1),1))) - |[0 ,1]|),p & a in Int (cell G,i,0 ) )thus
a in LSeg (((1 / 2) * ((G * i,1) + (G * (i + 1),1))) - |[0 ,1]|),
p
by RLTOPSP1:69;
a in Int (cell G,i,0 )thus
a in Int (cell G,i,0 )
by A1, Th36;
verum end;
hence
LSeg (((1 / 2) * ((G * i,1) + (G * (i + 1),1))) - |[0 ,1]|),p meets Int (cell G,i,0 )
by XBOOLE_0:3; verum