theorem Th5: :: GOBRD13:12

for i1, i2, j1 being Nat
for G1, G2 being Go-board st Values G1 c= Values G2 & [i1,j1] in Indices G1 & 1 <= i2 & i2 <= len G2 & G1 * (i1,j1) = G2 * (i2,(width G2)) holds
j1 = width G1