On Wed Nov 3 22:06:01 EDT 2010 [2 -3 0] M0 := [0 3 2] , TraceM0 = 12 [8 1 7] [1 5 -1] C1 := [0 2 5] [0 1 3] > M1 := MI(C1) . M0 . C1 ; TraceM1 := Trace(M1) ; [218 1199 133] M1 := [-40 -221 -27] , TraceM1 = 12 [ 16 90 15] [27 5 2] C2 := [ 5 29 17] [ 2 17 10] > M2 := MI(C2) . M0 . C2 ; TraceM2 := Trace(M2) ; [ 6080 3063 1598] M2 := [-101085 -50994 -26609] , TraceM2 := 12 [ 170652 86096 44926] ## So each two of M0, M1, M2 are conjugate-equivalent. And we saw that each has trace=12. Now let's compute their characteristic-polynomials. Firstly, [1 0 0] I3 := [0 1 0] [0 0 1] > charpoly0 := Det(M0 - x*I3); 2 3 charpoly0 := -10 - 39 x + 12 x - x > charpoly1 := Det(M1 - x*I3); 2 3 charpoly1 := -10 - 39 x + 12 x - x > charpoly2 := Det(M2 - x*I3); 2 3 charpoly2 := -10 - 39 x + 12 x - x ## Indeed, the three char-polys are equal. ================================================================