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
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&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; User manual for <a href="http://www.singular.uni-kl.de/"><i>Singular</i></a> version 2-0-4, October 2002,
generated by <a href="http://www.gnu.org/software/texinfo/"><i>texi2html</i></a>.
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