Top
Back: pnormalf
Forward: Prep
FastBack:
FastForward:
Up: grobcov_lib
Top: Singular Manual
Contents: Table of Contents
Index: Index
About: About this document

D.2.4.5 Crep

Procedure from library grobcov.lib (see grobcov_lib).

Usage:
Crep(ideal N,ideal M);
ideal N (null ideal) (not necessarily radical nor
maximal) in Q[a]. (a=parameters, x=variables).
ideal M (hole ideal) (not necessarily containing N)
in Q[a]. To be called in a ring Q[a][x] or a ring Q[a]. But the ideals can contain only the parameters
in Q[a].

Return:
The canonical C-representation [P,Q] of the
locally closed set, formed by a pair of radical
ideals with P included in Q, representing the set
V(P) \ V(Q) = V(N) \ V(M)

Example:
 
LIB "grobcov.lib";
short=0;
if(defined(R)){kill R;}
ring R=0,(a,b,c),lp;
ideal p=a*b;
ideal q=a,b-2;
// C-representation of V(p) \ V(q)
Crep(p,q);
==> [1]:
==>    _[1]=ab
==> [2]:
==>    _[1]=b-2
==>    _[2]=a


Top Back: pnormalf Forward: Prep FastBack: FastForward: Up: grobcov_lib Top: Singular Manual Contents: Table of Contents Index: Index About: About this document
            User manual for Singular version 4.3.1, 2022, generated by texi2html.