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help on the function reduce

help on the function reduce

wolf · Mon Jan 12, 2015 9:28 pm

Hello everyone,

I meet a problem when I use the Singular function reduce. I first compute a standard basis as follows, and the result is correct.

> ring B=0,(x,y,u),(a(1,1,-1),dp);
> poly f=-2x4-2x2y2+5x2y+y3-2y2;
> ideal i=jacob(f);
> ideal k=i,u-f;
> ideal G=std(k);
> G;
G[1]=18xy2-27xy+64xu
G[2]=45x2+9y2-32x2u-36y-27u
G[3]=u
G[4]=4y3+25x2-y2-20y-16u

But when I type

reduce(x2,G);

Singular seems to die. Is there anyone who knows why this happens? Thank you in advance!

Re: help on the function reduce

hannes · Tue Jan 13, 2015 5:00 pm

Thanks for the report: here ecart was computed in a wrong way leading to
a "never ending" reduce function. It is now fixed in the sources.
For the time being you may use

reduce(x2,G,1);

Re: help on the function reduce

wolf · Tue Jan 13, 2015 7:02 pm

Ok, thanks! when this problem is fixed, would you please let me know that? Thank you!