# ApCoCoA-1:CharP.GBasisF512

 This article is about a function from ApCoCoA-1.

## CharP.GBasisF512

Computing a Groebner Basis of a given ideal in F_512.

### Syntax

```CharP.GBasisF512(Ideal:IDEAL):LIST
```

### Description

Please note: The function(s) explained on this page is/are using the ApCoCoAServer. You will have to start the ApCoCoAServer in order to use it/them.

This command computes a Groebner basis in the field F_512 = (Z/(2))[x]/(x^9 + x +1).

• @param Ideal An Ideal in a Ring over Z, where the elements 0,...,511 represent the elements of the field. For short, the binary representation of the number represents the coefficient vector if the polynomial in the field, e.g. 11 = 8 + 2 + 1 = 2^3 + 2^1 + 2^0. So the number 11 corresponds to the polynomial x^3 + x + 1.

• @return A Groebner Basis of the given ideal.

#### Example

```Use R::=QQ[x,y,z];
I:=Ideal(x-y^2,x^2+xy,y^3);
GBasis(I);

[x^2 + xy, -y^2 + x, -xy]
-------------------------------
Use Z::=ZZ[x,y,z];
-- WARNING: Coeffs are not in a field
-- GBasis-related computations could fail to terminate or be wrong

-------------------------------
I:=Ideal(x-y^2,x^2+xy,y^3);
CharP.GBasisF512(I);
-- WARNING: Coeffs are not in a field
-- GBasis-related computations could fail to terminate or be wrong
-- CoCoAServer: computing Cpu Time = 0
-------------------------------
[y^2 + 256x, x^2, xy]
-------------------------------
```