# Difference between revisions of "ApCoCoA-1:Weyl.WNR"

## Weyl.WNR

Computes normal remainder of a Weyl polynomial F with respect

to a polynomial L or a set of polnomials in the list L.

### Syntax

```Weyl.WNR(F:POLY,G:LIST/POLY):POLY
```

### Description

Computes normal remainder of a Weyl polynomial F with respect to a polynomial L or a set of polynomials in the list L.

If L is Groebner basis then this function is used for ideal membership problem.

F: a Weyl polynomial in normal form.

L: a Weyl polynomial or a list of Weyl polynomials.

Output is a remainder R as a weyl polynomial using normal remainder algorithm in Weyl algebra A_n.

#### Example

```W3::=ZZ/(7)[x[1..3],d[1..3]];
Use W3;
F1:=-d^3d^5d^5+x^5;
F2:=-3xd^5d^5+xd^3;
F3:=-2d^4d^5-xd^7+x^3d^5;
L:=[F1,F2,F3];
Weyl.WNR(F1,L);
0
-------------------------------
Weyl.WNR(F1,Gens(Ideal(F2,F3)));
-d^3d^5d^5 + x^5
-------------------------------
Weyl.WNR(x^5-d^3,L);
x^5 - d^3
-------------------------------
Weyl.WNR(x^5-d^3d^7d^6,F1);
-x^5d^2d - 3x^4dd + x^5 + x^3d
-------------------------------
```

Note: All polynomials that are not in normal form should be first converted in to normal form using Weyl.WNormalForm(L), otherwise you may get unexpected results.