Re: Working modulo 2

• To: mathgroup at smc.vnet.net
• Subject: [mg92089] Re: Working modulo 2
• From: "David Park" <djmpark at comcast.net>
• Date: Sat, 20 Sep 2008 04:55:36 -0400 (EDT)
• References: <gavt0g\$g4u\$1@smc.vnet.net>

```expr = 7 + x + 4 y + 4 x y + 3 z + 2 x z + 4 y z + 4 x y z

expr /. x_Integer :> Mod[x, 2]
1 + x + z

Or better:

PolynomialMod[expr, 2]
1 + x + z

There are various methods to search the documentation. One convenient method
is to evaluate ?*keyword* to obtain all the commands that contain the
keyword. So

?*Polynomial*

gives us a list of functions that includes PolynomialMod.

--
David Park
djmpark at comcast.net
http://home.comcast.net/~djmpark/

"me13013" <me13013 at gmail.com> wrote in message
news:gavt0g\$g4u\$1 at smc.vnet.net...
> Howdy,
>
> How does one reduce a polynomial's coefficients modulo 2?  For
> example, I have a function that sums several polynomials, and
> currently produces a result like this:
>  7 + x + 4 y + 4 x y + 3 z + 2 x z + 4 y z + 4 x y z
> I want to reduce this to
>  1 + x + z
>
> I thought I might be able to do this by somehow coercing the terms
> into a list and then doing Sum[L[[i]],{i,1,Length[L]},Modulus->2], but
> no such luck.
>
> Any ideas?
>
> Thanks,
> Bob H
>

```

• Prev by Date: Re: Functional programming? (RPN -v- Algebraic)
• Next by Date: Re: Re: weird NMaximize behaviour
• Previous by thread: Re: Working modulo 2
• Next by thread: NDSolve and Piecewise