# Checker for O'N # Check orders of a, b and ab chor 1 2 chor 2 4 mu 1 2 3 chor 3 11 # We construct an element of order 5 which commutes with # b, thus proving that b is in 4A (as |C(4B)|=256). mu 2 2 4 mu 3 3 5 cj 4 5 6 mu 4 6 7 pwr 5 7 8 mu 5 8 9 # abab(b^2(b^2)^(abab))^5; it commutes with b chor 9 5 com 2 9 10 chor 10 1