theorem :: GOBOARD6:70

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