Changeset 2bbd4a in git

Timestamp:

May 19, 2014, 4:40:21 PM (9 years ago)

Author:

Anne Frühbis-Krüger <anne@…>

Branches:

(u'spielwiese', '8e0ad00ce244dfd0756200662572aef8402f13d5')

Children:

46c7c3543716f62ef5bb7e5989d0c0876634829a

Parents:

4bc25c236b0d155b3b1e4ab40855eacaaa27c3eb

Message:

fixed corner case (minimal resolution very short) in AnnExt_R

File:

• Singular/LIB/primdec.lib (modified) (1 diff)

Singular/LIB/primdec.lib

@@ -3995 +3995 @@
   if(n<nvars(basering))
   {
-     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
-  }
-  else
-  {
-     ideal ann=Ann(transpose(re[n]));
-  }
+    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]));
   return(ann);
 }