incorrect factorization by minAssChar()

[kroeker@…]

this is a followup to ticket 667.

failing example:

LIB("primdec.lib");
ring rng = (0),(xy,xt,xo,xu,xj,xx,xs,xz),dp;
ideal I = -17*xy*xj^2*xx*xz-26*xt*xs+17*xj,24*xy^2*xt*xo^2+12*xy,-10*xy-7*xt*xu^2*xj*xx*xz-25*xj;
def L1 = minAssGTZ(I);
def L2 = minAssChar(I);
L2;
minAssChar(L2[2]); //  size is 2
minAssChar(L2[3]); //  size is 2

output

> L2;
[1]:
   _[1]=xj
   _[2]=xt
   _[3]=xy
[2]:
   _[1]=xy
   _[2]=26*xt*xs-17*xj
   _[3]=119*xu^2*xj*xx*xz+650*xs
[3]:
   _[1]=130*xt*xs-34*xy-85*xj
   _[2]=119*xu^2-1625*xj*xs
   _[3]=5*xj^2*xx*xz+2
   _[4]=2*xy^2*xt*xo^2+xy
   _[5]=34*xy^3*xo^2+85*xy^2*xo^2*xj+65*xy*xs
[4]:
   _[1]=2*xy*xt*xo^2+1
   _[2]=17*xy*xj^2*xx*xz+26*xt*xs-17*xj
   _[3]=7*xu^2*xj*xx*xz-20*xy^2*xo^2-50*xy*xo^2*xj
   _[4]=182*xt^2*xu^2*xs-119*xt*xu^2*xj-170*xy^2*xj-425*xy*xj^2
   _[5]=52*xt^2*xo^2*xs-34*xt*xo^2*xj-17*xj^2*xx*xz
   _[6]=340*xy^3*xo^2*xj+850*xy^2*xo^2*xj^2+182*xt*xu^2*xs-119*xu^2*xj
   _[7]=6800*xy^5*xo^4+106250*xy^2*xo^4*xj^3+1274*xt*xu^4*xx*xs*xz+22750*xt*xo^2*xu^2*xj*xs-2380*xy^2*xo^2*xu^2+5950*xy*xo^2*xu^2*xj-14875*xo^2*xu^2*xj^2+9100*xu^2*xs
> 
> minAssChar(L2[2]);
[1]:
   _[1]=xy
   _[2]=26*xt*xs-17*xj
   _[3]=119*xu^2*xj*xx*xz+650*xs
   _[4]=7*xt*xu^2*xx*xz+25
[2]:
   _[1]=xs
   _[2]=xj
   _[3]=xy
> minAssChar(L2[3]);
[1]:
   _[1]=130*xt*xs-34*xy-85*xj
   _[2]=119*xu^2-1625*xj*xs
   _[3]=5*xj^2*xx*xz+2
   _[4]=2*xy*xt*xo^2+1
   _[5]=34*xy^2*xo^2+85*xy*xo^2*xj+65*xs
[2]:
   _[1]=xy
   _[2]=26*xt*xs-17*xj
   _[3]=119*xu^2-1625*xj*xs
   _[4]=5*xj^2*xx*xz+2

[hannes]

fix: 66fa7159e6605255e24cc1278b31fb5bb0e9f109 is really part of tr. #667