On Mar 26, 2007, at 12:24 , Timothy Clemans wrote:

>
> I just want to tell the user of my factoring apps when the quadratic
> that they submit is prime. I've tried is_prime, and
> len(factor(x^2+B*x+C)) (thinking an answer of one would mean its
> prime, but it does not mean that). What is the best way in SAGE right
> now to test a polynomial over ZZ to tell if it is irreducible over ZZ?

I think is_prime() is just for integers.

You should be able to infer that a polynomial is irreducible if factor 
() returns a value with length 1.  Why don't you think that will work?

There may be a few kinks in the strategy, depending on the kind of  
polynomial the user hands you, though.

You can always verify that a quadratic polynomial over ZZ is  
irreducible over ZZ by doing it the hard way: compute the roots; if  
they are both integers, the polynomial is reducible over ZZ; else  
not :-}.

Justin

--
Justin C. Walker, Curmudgeon at Large
Institute for the Absorption of Federal Funds
-----------
My wife 'n kids 'n dogs are gone,
I can't get Jesus on the phone,
But Ol' Milwaukee's Best is my best friend.
-----------



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