theorem Th6: :: JORDAN15:6

for G being Go-board
for i, j, k, j1, k1 being Nat st 1 <= i & i <= width G & 1 <= j & j <= j1 & j1 <= k1 & k1 <= k & k <= len G holds
LSeg ((G * (j1,i)),(G * (k1,i))) c= LSeg ((G * (j,i)),(G * (k,i)))