theorem Th20: :: JORDAN1I:20
for f being constant standard clockwise_oriented special_circular_sequence
for G being Go-board st f is_sequence_on G holds
for i, j, k being Nat st 1 <= k & k + 1 <= len f & [i,j] in Indices G & [i,(j + 1)] in Indices G & f /. k = G * (i,(j + 1)) & f /. (k + 1) = G * (i,j) holds
(f /. k) `1 <> W-bound (L~ f)