theorem Th29: :: SPRECT_3:29

for i being Nat
for f being constant standard clockwise_oriented special_circular_sequence st i in dom (GoB f) & f /. 1 = (GoB f) * (i,(width (GoB f))) & f /. 1 = N-min (L~ f) holds
( f /. 2 = (GoB f) * ((i + 1),(width (GoB f))) & f /. ((len f) -' 1) = (GoB f) * (i,((width (GoB f)) -' 1)) )