"pNorm not possible in the case of coefficient rings."

[Martin Albrecht]

This looks like a bug to me:

                     SINGULAR                             /
 A Computer Algebra System for Polynomial Computations   /   version 3-1-0
                                                       0<
     by: G.-M. Greuel, G. Pfister, H. Schoenemann        \   Mar 2009
FB Mathematik der Universitaet, D-67653 Kaiserslautern    \
> ring r= (integer),(x,y,z),dp;
// ** You are using coefficients rings which are not fields.
// ** Please note that only limited functionality is available
// ** for these coefficients.
// **
// ** The following commands are meant to work:
// ** - basic polynomial arithmetic
// ** - std
// ** - reduce
> poly f = 9*z^2 + 1458*x + 19683*y + 54;
> ideal i = 9*x + 243*y - 27*z, z^3 - x;
> reduce(f,i);
// ** i is no standard basis
   ? pNorm not possible in the case of coefficient rings.
   ? error occurred in STDIN line 4: `reduce(f,i);`
> reduce(f,std(i));
   ? pNorm not possible in the case of coefficient rings.
   ? error occurred in STDIN line 5: `reduce(f,std(i));`

[dreyer]

Curious: Using lp, the same examples is working... Regards,

Alexander

[hannes]

tail reduction was not implemented for coeffs of type ring.. Now an implmentation exists for Z, but needs to be extended for Z/m etc.