In Singular the behaviour of deg() changed between v3.1.7 and v 4.0.3.
Question:
- Which answer is correct ?
- Which of the answers users really expected?
Code:
SINGULAR / Development
A Computer Algebra System for Polynomial Computations / version 3-1-7
0<
by: W. Decker, G.-M. Greuel, G. Pfister, H. Schoenemann \ Aug 2013
FB Mathematik der Universitaet, D-67653 Kaiserslautern \
// ** executing /run/media/jakob/TOEXT4/work/home_fc18/Projects/lipmanresolve/Singular-3-1-7/Singular/LIB/.singularrc
> ring rng = 0,(x,y,z),dp;
>
. intmat im[3][3] = 3,0,1,1,1,0,1,0,0;
> ring S = 0,(x,y,z),(M(im));
> S;
// characteristic : 0
// number of vars : 3
// block 1 : ordering M
// : names x y z
// : weights 3 0 1
// : weights 1 1 0
// : weights 1 0 0
// block 2 : ordering C
> poly p = x^3*y+x*z^4;
>
. deg(p);
9
> quit;
Auf Wiedersehen.
[jakob@vogon lipmanresolve]$ ./singular-spielwiese
SINGULAR / Development
A Computer Algebra System for Polynomial Computations / version 4.0.3
0<
by: W. Decker, G.-M. Greuel, G. Pfister, H. Schoenemann \ Jan 2016
FB Mathematik der Universitaet, D-67653 Kaiserslautern \
// ** executing /run/media/jakob/TOEXT4/work/home_fc18/Projects/lipmanresolve/Singular-spielwiese/BUILD/Singular/LIB/.singularrc
> ring rng = 0,(x,y,z),dp;
>
. intmat im[3][3] = 3,0,1,1,1,0,1,0,0;
> ring S = 0,(x,y,z),(M(im));
> S;
// characteristic : 0
// number of vars : 3
// block 1 : ordering M
// : names x y z
// : weights 3 0 1
// : weights 1 1 0
// : weights 1 0 0
// block 2 : ordering C
> poly p = x^3*y+x*z^4;
>
. deg(p);
5
Remark: the changes also affects software which depends on Singular