From e2717632d5530a47f399fdf9a21ab1951423945c Mon Sep 17 00:00:00 2001
From: Nelynx <nbreva@gmail.com>
Date: Thu, 27 Feb 2025 16:33:03 +0100
Subject: [PATCH] add option to work modulo an ideal

---
 .singularhistory | 33 +++++++++++++++++++++++++++++
 AeCodPruebas.lib | 55 +++++++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 85 insertions(+), 3 deletions(-)

diff --git a/.singularhistory b/.singularhistory
index 0e210ae..387b5bc 100644
--- a/.singularhistory
+++ b/.singularhistory
@@ -12,3 +12,36 @@ f = imap(s,f);
 f;
 kbase(std(f));
 quit;
+LIB"AeCodPruebas.lib";
+ring r = 0,(x,y),ds;
+ideal f = x,y2,y3+x2y;
+def Q = MalgrRing(ideal(0),2,f);
+setring Q;
+TargetIdeal(ideal(x,y));
+LIB"AeCodPruebas.lib";
+TargetIdeal(ideal(x,y));
+LIB"AeCodPruebas.lib";
+TargetIdeal(ideal(x,y));
+LIB"AeCodPruebas.lib";
+TargetIdeal(ideal(x,y));
+LIB"AeCodPruebas.lib";
+TargetIdeal(ideal(x,y));
+LIB"AeCodPruebas.lib";
+TargetIdeal(ideal(x,y));
+LIB"AeCodPruebas.lib";
+TargetIdeal(ideal(x,y));
+LIB"AeCodPruebas.lib";
+TargetIdeal(ideal(x,y));
+LIB"AeCodPruebas.lib";
+TargetIdeal(ideal(x,y));
+ring r = 0,(x,y),ds;
+ideal f = x,y2,y3+x2y;
+LIB"AeCodPruebas.lib";
+TargetIdeal(f, ideal(x,y));
+TargetIdeal(f, std(ideal(x,y)));
+LIB"AeCodPruebas.lib";
+TargetIdeal(f, std(ideal(x,y)));
+LIB"AeCodPruebas.lib";
+ring r = 0,(x,y),ds;
+ideal f = x,y2,y3+x2y;
+TargetIdeal(f, std(ideal(x,y)));
diff --git a/AeCodPruebas.lib b/AeCodPruebas.lib
index b556470..b63cb69 100644
--- a/AeCodPruebas.lib
+++ b/AeCodPruebas.lib
@@ -123,6 +123,13 @@ proc AeNormal(ideal f, list #)
    int n = nvars(basering);
    int p = ncols(f);
 
+   int s = size(#);
+
+   if (s > 0)
+   {
+      int k = TargetIdeal(f,std(#[1]));
+   }
+
    def Raux = MalgrRing(ideal(0),n,ideal(f[1..n]));
 
    matrix jf[p][n] = jacob(f);
@@ -133,7 +140,11 @@ proc AeNormal(ideal f, list #)
 
    execute("def f = imap("+RName+",f)");
    execute("def jf = imap("+RName+",jf)");
-   execute("def # = imap("+RName+",#)");
+
+   if (s > 0)
+   {
+      execute("def # = imap("+RName+",#)");
+   }
 
    module wf = freemodule(p);
    int m = ncols(Gens);
@@ -150,6 +161,11 @@ proc AeNormal(ideal f, list #)
       }
    }
 
+   if (s>0)
+   {
+      wf = wf + freemodule(p)*(f^k);
+   }
+
    if (size(#)>0)
    {
       jf = jf + #[1]*freemodule(p);
@@ -218,6 +234,39 @@ proc NormalOYModule(matrix GOX, matrix GOY, list #)
 
 //////////////////////////////////////////////////////////////////////////////
 
+
+proc TargetIdeal(ideal f, ideal J)
+{
+   /*
+      Ideal f should be a finite map.
+      Ideal J should be an ideal in O_X in STD form, such that the radical of J is the maximal ideal.
+      OUTPUT: An integer k such that f^k is contained in J.
+   */
+
+   int done = 0;
+   int k = 1;
+   
+   ideal auxf = 1;
+   
+   while (done == 0)
+   {
+      auxf = auxf*f;
+      if (size(reduce(auxf,J,1)) == 0)
+      {
+         done = 1;
+      }
+      else
+      {
+         k++;
+      }
+   }
+   
+   return(k);
+
+}
+
+//////////////////////////////////////////////////////////////////////////////
+
 proc GenerateOYModule(matrix GOX, matrix GOY, list #)
 {
    /*
@@ -383,7 +432,7 @@ proc MalgrFormPoly(poly h, list #)
    {
       K = std(#[1]+GF);    // Work modulo an ideal, if requested.
    }
-
+   
    for (i=dimX+1; i <= size(mappingf); i++)
    {
       K = K + ideal(X(i) - reduce(mappingf[i], K));   // Assign the components of f which do not give the finite mapping to variables in the target, if p > n.
@@ -399,7 +448,6 @@ proc MalgrFormPoly(poly h, list #)
    poly c;
    int nGens = ncols(Gens);
 
-   
    // Convert the Malgrange Normal Form of the polynomial to row matrix form.
 
    /*
@@ -408,6 +456,7 @@ proc MalgrFormPoly(poly h, list #)
    We only need to extract these coefficients and add them to the corresponding component in v.
    */
 
+
    matrix v[1][nGens] = 0; 
    
    for (i=1; i<= nGens-1; i++)