|
D.4.9.5 closureFrac
Procedure from library reesclos.lib (see reesclos_lib).
- Create:
- a list fraction of two elements of L[1], such that
f=fraction[1]/fraction[2] via the injections phi L[i]-->L[i+1].
Example:
| LIB "reesclos.lib";
ring R=0,(x,y),dp;
ideal ker=x2+y2;
export R;
==> // ** `R` is already global
list L=primeClosure(R); // We normalize R/ker
closureRingtower(L); // Now R/ker=R(1) with normalization R(2)
setring R(2);
kill(R);
phi; // The map R(1)-->R(2)
==> phi[1]=T(1)*T(2)
==> phi[2]=T(1)
poly f=T(1)*T(2); // We will get a representation of f
export R(2);
==> // ** `R(2)` is already global
closureFrac(L);
setring R(1);
kill (R(2));
fraction; // f=fraction[1]/fraction[2] via phi
==> [1]:
==> xy
==> [2]:
==> y
|
|