theorem Th54:
for
i being
Nat for
G being
Go-board st 1
<= i &
i < len G holds
LSeg (
(((1 / 2) * ((G * (i,(width G))) + (G * ((i + 1),(width G))))) + |[0,1]|),
((G * (i,(width G))) + |[0,1]|))
c= (Int (cell (G,i,(width G)))) \/ {((G * (i,(width G))) + |[0,1]|)}