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Hello,

I'm having a problem finding the minimal polynomial of a rational

matrix A. MinimalPolynomial(A) first finds D = Domain([A]), and

then applies D.operations.MinimalPolynomial. Unfortunately, if

A is a rational matrix, then Domain([A]) returns Matrices, and

Matrices.operations.MinimalPolynomial is unbound. Is there any

reason why for a rational matrix A, Domain([A]) doesn't return

FieldMatrices? (FieldMatrices.operations.MinimalPolynomial exists.)

I tried to get around this by simply setting

Matrices.operations.MinimalPolynomial :=

FieldMatrices.operations.MinimalPolynomial;

This seems to work for rational matrices A, and indeed there is

nothing in the code for FieldMatrices.operations.MinimalPolynomial

that makes any assumptions about the field. However, I also tested

matrices over cyclotomic fields, and ran into difficulties, because

for a cyclotomic field F GAP seems to be unable to compute Euclidean

quotients in F[x] (that is, the ring of polynomials in x over the

field F, not the xth element of the list F). This is puzzling,

but since I'm mainly interested in rational matrices I didn't chase

it down any further.

Any help or advice would be greatly appreciated.

-- Robert Beals

P.S. I'm using version 3 release 3.

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