Thurs Feb 3 * isometries in S4, A4, C4, D4, S5, A5, C5, D5 * properties of individual elements: - cycle length - commutator of something? (define "communtator") * discuss solid cube group (starting this was the homework assignment) 1 Identity (cycle length = 1) 6 F, R, U, F', R', U' (cycle length = 4; 90 degree face-centered rotation) 3 F2, R2, U2 (cycle length = 2; 180 degree face-centered rotation) 8 FR etc (cycle length = 3; 120 degree corner-centered rotation) 6 RRU etc (cycle length = 2; 180 degree edge-centered rotation) --- sum = 24 * treat R,F,U,R',F',U' as generators; draw the graph for this 24 element group * Are R,F,U generators? R,F? R? Any single element? * odd/even * notation on rubik's cube; commutators; cycle length (assign) * time allowing : matrix multiplication rules permutation matrices * for Thurs Feb 10 1.Find the commutator subgroup of the solid cube group. 2.Do R, F generate the cube group? R,F,U? R?? 3.What is the cycle length of the Rubik's commutator FRF'R' ? FR ? - next time: * if c = a b a' then we say "c and b are conjugate". * conjugacy classes * conjugacy classes of solid cube