CoCoA » CoCoA-5

I was recently asked how to compute with parameters. It is not easy to find this out from the documentation. So make better doc!

Here is the example I created "on the fly":

/**/ Qa ::= QQ[a];
/**/ k := NewFractionField(Qa);
/**/ P ::= k[x,y];
/**/ use P;
/**/ I := ideal(x^2+y^2-a^2, x-y);
/**/ ReducedGBasis(I);
[x -y,  y^2 +(-a^2)/2]
/**/ I := ideal(x^2+y^2-a^2, a*x-y);
/**/ ReducedGBasis(I);
[x +(-1/a)*y,  y^2 +(-a^4)/(a^2 +1)]