Opened 8 years ago

Closed 8 years ago

primdecGTZ fails to decompose ideal correctly

Reported by: Owned by: kroeker@… somebody minor 4-1-0 and higher singular-libs 4-0-1 primary decomposition bug

Description

primdecGTZ() fails to decompose ideal correctly,

see second entry of decomposition L1.

```LIB("primdec.lib");
ring rng = (0),(xa,xr,xv,xn,xg,xt,xh,xo),dp;
ideal I = -30*xa*xv*xt^3+2*xt,
25*xr*xh+29*xv*xn^2*xt*xh^2+19,
-18*xa*xr^2*xo^2+24*xa*xv*xn*xt*xh*xo+2*xa;

list L1 = primdecGTZ (I);
L1[2][1];
list pc2 =  primdecGTZ(L1[2][1]);
pc2;
ASSUME(0, size( pc2) ==1); // fail!
```

output

```. list L1 = primdecGTZ (I);
> L1[2][1];
_[1]=625*xh^2-3249*xo^2
_[2]=xt
_[3]=171*xr*xo^2+25*xh
_[4]=25*xr*xh+19
> list pc2 =  primdecGTZ(L1[2][1]);
> pc2;
[1]
[1]
_[1]=25*xh-57*xo
_[2]=3*xr*xo+1
_[3]=xt
[2]
_[1]=25*xh-57*xo
_[2]=3*xr*xo+1
_[3]=xt
[2]
[1]
_[1]=25*xh+57*xo
_[2]=3*xr*xo-1
_[3]=xt
[2]
_[1]=25*xh+57*xo
_[2]=3*xr*xo-1
_[3]=xt
```

comment:1 Changed 8 years ago by Oleksandr

incomplete factorization over QQ

comment:2 Changed 8 years ago by hannes

Resolution: → fixed new → closed

fixed by mlee with 8eec294f01ff794d6970f9b1dc8693a5ca131146 (see tr #656, #659)

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