PolynomialRemainder[p, q, x] gives the remainder from dividing p by q, treated as polynomials in x. Regards, Bill -----Original Message----- From: math-fun-bounces@mailman.xmission.com [mailto:math-fun-bounces@mailman.xmission.com] On Behalf Of Dan Asimov Sent: Friday, February 29, 2008 11:38 AM To: math-fun Subject: [math-fun] Help with polynomial calculations in Mathematica or Maple I find I quickly lose patience when the online "help" files in either of these packages doesn't seem to be helping no matter how I phrase my query. Can someone please tell me how to accomplish the following: I want to multiply out some polynomials (with symbolic coefficients) to get a big hairy polynomial (so far no problem) . . . and then reduce the result modulo setting certain (small) polynomials equal to 0. (It seems that in Mathematica's Simplify command, the Assumptions parameter is intended to do just this. But apparently I can't figure out the syntax, and the "help" files aren't telling.) (What I tried was Simpify[hairypolynomial, {smallpoly = 0}] but it didn't like the syntax for {smallpoly = 0}.) Thanks in advance for any assistance with this. --Dan P.S. In an alternative attempt to get Mathematica to enforce the simple condition that x^5 = 1, I tried just setting x = Exp[2 Pi i/5]. It certainly understood this, since when I typed x^5 it responded with: 2 i Pi Out[2]= E . But an attempt to Simplify that expression left it unchanged. _____________________________________________________________________ "It don't mean a thing if it ain't got that certain je ne sais quoi." --Peter Schickele _______________________________________________ math-fun mailing list math-fun@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun

You understand, do you not, that in Mathematica, the square root of -1 is written as I, not as i? Good luck! Alan Schoen Dan Asimov wrote:

I find I quickly lose patience when the online "help" files in either of these packages doesn't seem to be helping no matter how I phrase my query.

Can someone please tell me how to accomplish the following:

I want to multiply out some polynomials (with symbolic coefficients) to get a big hairy polynomial (so far no problem) . . . and then reduce the result modulo setting certain (small) polynomials equal to 0.

(It seems that in Mathematica's Simplify command, the Assumptions parameter is intended to do just this. But apparently I can't figure out the syntax, and the "help" files aren't telling.)

(What I tried was

Simpify[hairypolynomial, {smallpoly = 0}]

but it didn't like the syntax for {smallpoly = 0}.)

Thanks in advance for any assistance with this.

--Dan

P.S. In an alternative attempt to get Mathematica to enforce the simple condition that x^5 = 1, I tried just setting x = Exp[2 Pi i/5]. It certainly understood this, since when I typed x^5 it responded with:

2 i Pi Out[2]= E

.

But an attempt to Simplify that expression left it unchanged.

_____________________________________________________________________ "It don't mean a thing if it ain't got that certain je ne sais quoi." --Peter Schickele

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