D.5.5.15 newtonpoly

Procedure from library hnoether.lib (see hnoether_lib).

Usage:

newtonpoly(f); f poly

Assume:

basering has exactly two variables;
f is convenient, that is, f(x,0) != 0 != f(0,y).

Return:

list of intvecs (= coordinates x,y of the Newton polygon of f).

Note:

Procedure uses execute; this can be avoided by calling newtonpoly(f,1) if the ordering of the basering is ls.

Example:

LIB "hnoether.lib";
ring r=0,(x,y),ls;
poly f=x5+2x3y-x2y2+3xy5+y6-y7;
newtonpoly(f);
→ [1]:
→    0,6
→ [2]:
→    2,2
→ [3]:
→    3,1
→ [4]:
→    5,0