theorem Th8: :: JORDAN9:8

for G being Go-board
for f being FinSequence of (TOP-REAL 2) st f is_sequence_on G holds
for k being Nat st 1 <= k & k + 1 <= len f holds
( f /. k in left_cell (f,k,G) & f /. k in right_cell (f,k,G) )