[seqfan] Re: Cannonicalizing factorization matrices

israel at math.ubc.ca israel at math.ubc.ca
Tue Aug 2 05:04:50 CEST 2016

What software is this in?  It doesn't seem like a well-designed interface
to the factoring algorithm.

In Maple, ifactors(n)[2] will produce something like
[[2,1],[3,1],[5,2]].  There are never repeats of primes or exponents of 0.
The primes are not necessarily in order, but you can sort the result.


On Aug 1 2016, Charles Greathouse wrote:

>It occasionally happens that I'm working with a number where it is
>convenient to manipulate its factored form. Sometimes I will end up with a
>matrix like
>[2, 1; 3, 0; 5, 2]
>(0 exponent) or
>[2, 2; 7, 1; 3, 1]
>(primes out of order). Conceivably it could even result in
>[2, 1; 3, 1; 2, 1]
>(primes appearing multiple times) although this has not happened to me yet.
>Is there a good/standard/recommended way to do this?
>Of course this can be achieved with factor(factorback(f)) but this throws
>away the information I'm trying to preserve.
>Charles Greathouse
>Case Western Reserve University
>Seqfan Mailing list - http://list.seqfan.eu/

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