Changeset dccf2b in git

Timestamp:

Aug 2, 2014, 2:36:29 PM (10 years ago)

Author:

Jakob Kroeker <kroeker@…>

Branches:

(u'spielwiese', 'fe61d9c35bf7c61f2b6cbf1b56e25e2f08d536cc')

Children:

1b27750259e61df6d2ca90f391c430a44660c92a

Parents:

8fec1744a3a9bea1854b58d99979f51ac2c46026

git-author:

Jakob Kroeker <kroeker@math.uni-hannover.de>2014-08-02 14:36:29+02:00

git-committer:

Jakob Kroeker <kroeker@math.uni-hannover.de>2014-08-02 14:47:41+02:00

Message:

bugfixes for 583, 611, 632

Files:

• Singular/LIB/primdec.lib (modified) (4 diffs)
• Tst/Short/bug_583.res.gz.uu (added)
• Tst/Short/bug_583.stat (added)
• Tst/Short/bug_583.tst (added)
• Tst/Short/bug_611.res.gz.uu (added)
• Tst/Short/bug_611.stat (added)
• Tst/Short/bug_611.tst (added)
• Tst/Short/bug_632.res.gz.uu (added)
• Tst/Short/bug_632.stat (added)
• Tst/Short/bug_632.tst (added)

Singular/LIB/primdec.lib

@@ -4091 +4091 @@
   list re=sres(i,0);                   //the resolution
   re=minres(re);                       //minimized resolution
-  ideal ann=AnnExt_R(e,re);
-  if(nvars(basering)-dim(std(ann))!=e)
-  {
-    return(ideal(1));
+  ideal ann = AnnExt_R(e,re);
+  if ( nvars(basering)-dim(std(ann)) != e )
+  {
+    return( ideal(1) );
   }
   return(ann);
@@ -4103 +4103 @@
 //computes the annihilator of Ext^n(R/i,R) with given resolution re
 //n is not necessarily the number of variables
+// !! borrowed correct code from 'ehv.lib::AnnExtEHV' by Kai Dehmann !! duplicate code!! (jk) 
+
 static proc AnnExt_R(int n,list re)
+"USAGE:   AnnExt_R(n,re); n integer, re resolution
+RETURN:  ideal, the annihilator of Ext^n(R/I,R) with given
+         resolution re of I
+"
 {
 
-  if(n<nvars(basering))
-  {
-    if(size(re[n+1])>0)
-    {
-        matrix f=transpose(re[n+1]);      //Hom(_,R)
-        module k=nres(f,2)[2];            //the kernel
-        matrix g=transpose(re[n]);        //the image of Hom(_,R)
-
-        ideal ann=quotient1(g,k);         //the anihilator
-        return(ann);
-    }
-  }
-  // remaining case: re[n+1] is trivial
-  // either n is at least number of variables or
-  // resolution happens to be shorter
-  ideal ann=Ann(transpose(re[n]));
+  if(n < 0)
+    {
+      ideal ann = ideal(1);
+      return(ann);
+    }
+  int l = size(re);
+
+  if(n < l)
+    {
+      matrix f = transpose(re[n+1]);
+      if(n == 0)
+        {
+          matrix g = 0*gen(ncols(f));
+        }
+      else
+        {
+          matrix g = transpose(re[n]);
+        }
+      module k = syz(f);
+      ideal ann = quotient1(g,k);
+      return(ann);
+    }
+
+  if(n == l)
+    {
+      ideal ann = Ann(transpose(re[n]));
+      return(ann);
+    }
+
+  ideal ann = ideal(1);  
   return(ann);
 }
@@ -6665 +6685 @@
   if(homog(i)==1)
   {
-     list re=sres(j,0);                   //the resolution
+     resolution re=sres(j,0);                   //the resolution
      re=minres(re);                       //minimized resolution
   }
@@ -6711 +6731 @@
   ideal j=groebner(i);
   int cod=nvars(basering)-dim(j);
+
+  
+  if(cod > nvars(basering))
+    {
+      dbprint(printlevel,"//If I is the entire ring...");
+      dbprint(printlevel,"//...then return the ideal generated by 1.");
+      return(ideal(1));
+    }
+
   int e;
   ideal ann;
   if(homog(i)==1)
   {
-     list re=sres(j,0);                   //the resolution
+     resolution re=sres(j,0);                   //the resolution
      re=minres(re);                       //minimized resolution
   }
   else
   {
-    list re=mres(j,0);
-  }
-  ann=AnnExt_R(cod,re);
+    resolution re=mres(j,0);
+  }
+  ann = AnnExt_R(cod,re);
+  if( nvars(basering)-dim(std(ann) ) != cod)
+  {
+     return( ideal(1) );
+  }
+
   return(ann);
 }