promdecSY(): example for failing primary decomposition using given ordering

[kroeker@…]

LIB("primdec.lib");
option(redTail);
option(redSB);
ring rng = (0),(x,y,z,w),lp;
ideal I = 
1003/1073*x*w^2+3856/1601*y^2-6193/5747*y*z+10820/19117*w,
-2779/1010*x+1505/1007*y^2,
9233/8945*z*w-6187/6861*w^2;

list L1 = primdecGTZ (I);
list L2 = primdecSY (I,0);
L1;
L2;

def pr2 = primdecSY( L2[2][1], 0  );
pr2;
size(pr2);

output:

> L1;
[1]:
   [1]:
      _[1]=w
      _[2]=22160432y-9914993z
      _[3]=x-217150/399779y2
   [2]:
      _[1]=w
      _[2]=22160432y-9914993z
      _[3]=x-217150/399779y2
[2]:
   [1]:
      _[1]=63347613z-55342715w
      _[2]=346693141932207724003884450y2w2+1644560582400204909487954032y2-642827240640245294954853115yw+386466366480719155407508620w
      _[3]=x-217150/399779y2
   [2]:
      _[1]=63347613z-55342715w
      _[2]=346693141932207724003884450y2w2+1644560582400204909487954032y2-642827240640245294954853115yw+386466366480719155407508620w
      _[3]=x-217150/399779y2
[3]:
   [1]:
      _[1]=w
      _[2]=y
      _[3]=x-217150/399779y2
   [2]:
      _[1]=w
      _[2]=y
      _[3]=x-217150/399779y2
> L2;
[1]:
   [1]:
      _[1]=63347613z-55342715w
      _[2]=346693141932207724003884450y2w2+1644560582400204909487954032y2-642827240640245294954853115yw+386466366480719155407508620w
      _[3]=399779x-217150y2
   [2]:
      _[1]=63347613z-55342715w
      _[2]=346693141932207724003884450y2w2+1644560582400204909487954032y2-642827240640245294954853115yw+386466366480719155407508620w
      _[3]=399779x-217150y2
[2]:
   [1]:
      _[1]=w
      _[2]=22160432y2-9914993yz
      _[3]=4429637672264x-1076520364975yz
   [2]:
      _[1]=w
      _[2]=22160432y-9914993z
      _[3]=98162684420844658048x-10673691883084570175z2
> 
. def pr2 = primdecSY( L2[2][1], 0  );
> pr2;
[1]:
   [1]:
      _[1]=w
      _[2]=y
      _[3]=x
   [2]:
      _[1]=w
      _[2]=y
      _[3]=x
[2]:
   [1]:
      _[1]=w
      _[2]=22160432y-9914993z
      _[3]=98162684420844658048x-10673691883084570175z2
   [2]:
      _[1]=w
      _[2]=22160432y-9914993z
      _[3]=98162684420844658048x-10673691883084570175z2
> size(pr2);
2

[hannes]

fixed by mlee with 0a2bb7f8162de3bcdab6581897d7bdbc6f7020ba