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D.2.4.15 AddCons

Procedure from library grobcov.lib (see grobcov_lib).

Usage:
AddCons(L)
Calls internally AddConsP and allows a different input. Input L: list of pairs of of ideals [ [P_1,Q_1], .., [Pr,Qr] ] representing a set of locally closed setsV(P_i) \ V(Q_i) to be added.

Return:
list of lists of levels of the different locally closed sets of the canonical P-rep of the constructible.
[ [level_1,[ [Comp_11,..Comp_1r_1] ] ], .. ,
[level_s,[ [Comp_s1,..Comp_sr_1] ] ] where level_i=i, Comp_ij=[ p_i,[p_i1,..,p_it_i] ] is a prime component.

Note:
Operates in a ring R=Q[u_1,..,u_m]

Example:
 
LIB "grobcov.lib";
if (defined(Grobcov::@P)){kill Grobcov::@P; kill Grobcov::@R; kill Grobcov::@RP;}
ring R=0,(x,y,z),lp;
short=0;
ideal P1=x;
ideal Q1=x,y;
ideal P2=y;
ideal Q2=y,z;
list L=list(list(P1,Q1), list(P2,Q2) );
L;
==> [1]:
==>    [1]:
==>       _[1]=x
==>    [2]:
==>       _[1]=x
==>       _[2]=y
==> [2]:
==>    [1]:
==>       _[1]=y
==>    [2]:
==>       _[1]=y
==>       _[2]=z
AddCons(L);
==> [1]:
==>    [1]:
==>       1
==>    [2]:
==>       [1]:
==>          [1]:
==>             _[1]=x
==>          [2]:
==>             [1]:
==>                _[1]=z
==>                _[2]=y
==>                _[3]=x
==>       [2]:
==>          [1]:
==>             _[1]=y
==>          [2]:
==>             [1]:
==>                _[1]=z
==>                _[2]=y