Hi Axiom wizards, I was experimenting with the Cayley-Hamilton theorem:
M:=matrix([[random(20) for i in 1..4] for j in 1..4]) p:=characteristicPolynomial(M,y) eval(p,y=M) and we get a matrix of zeros, as we should. It also works if we take elements from a finite field: M:=matrix([[random()$PF 7 for i in 1..4] for j in 1..4]) or M:=matrix([[random()$FF(2,4) for i in 1..4] for j in 1..4]) But it doesn't work for a finite field with a defining polynomial: M:=matrix([[random()$FFP(PF 2,x^4+x+1) for i in 1..4] for j in 1..4]) The next two commands produce:
Error detected within library code:
coerce: element doesn't belong to smaller field What's going on, and why? Thanks, Alasdair
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