std(stdI,J) not reduced with disabled 'redTail' and enabled 'redSB'

[kroeker@…]

failing example:

ring rng = (167),(x,y,z),(dp(3),C);
short = 0 ;
option(noredTail);
option(redSB);
system("random", 1300476452);
ideal I = 20*y*z-44;
ideal J = -15*x*z-24,5*x*y^2+33*x-1;
   ideal gI   =  std(I);
   ideal IJ   = I+J;
   ideal gIJ  = std(IJ);
   ideal gI_J = std(gI,J);
ASSUME(0, 0== size( std(reduce (I,gI ) ))  );
ASSUME(0, 0== size( std(reduce (IJ,gIJ ) ))  ); 
reduce (IJ, gI_J );

output

_[1]=0
_[2]=0
_[3]=33*x+24*y

[kroeker@…]

update: faulty bug report; gI_J is even not standard basis:

> gI_J;
gI_J[1]=z^2+76*x-14*z
gI_J[2]=y*z-69
gI_J[3]=x*z+35
gI_J[4]=x*y-76*z+62
gI_J[5]=x^2-51*z+46
> std(gI_J);
_[1]=x-60*y
_[2]=z^2+51*y-14*z
_[3]=y*z-69
_[4]=y^2+21*z+40

[Oleksandr]

it may be related to std(I, J) not being a GB...

=> fix postponed until the other ticket is fixed

[hannes]

see tr. #712