Top
Back: checkRoot1
Forward: checkFactor
FastBack: central_lib
FastForward: involut_lib
Up: dmod_lib
Top: Singular Manual
Contents: Table of Contents
Index: Index
About: About this document
7.5.2.0. checkRoot2
Procedure from library dmod.lib (see dmod_lib).

Usage:
checkRoot2(I,f,alpha [,eng]); I an ideal, f a poly, alpha a number, eng an optional int

Assume:
I is the annihilator of f^s in D[s], f is a polynomial in K[_x]

Return:
int, the multiplicity of -alpha as a root of the global Bernstein polynomial of f. If -alpha is not a root, the output is 0

Purpose:
check whether a rational is a root of the global Bernstein polynomial of f and compute its multiplicity from the known Ann F^s in D[s]

Note:
If eng <>0, std is used for Groebner basis computations,
otherwise (and by default) slimgb is used.
If printlevel=1, progress debug messages will be printed,
if printlevel>=2, all the debug messages will be printed.

Example:
 
LIB "dmod.lib";
ring r = 0,(x,y,z),Dp;
poly F = x*y*z;
printlevel = 0;
def A = Sannfs(F);
setring A;
poly F = imap(r,F);
checkRoot2(LD,F,1);    // -1 is a root of bs with multiplicity 3
==> 3
checkRoot2(LD,F,1/3);  // -1/3 is not a root
==> 0


Top Back: checkRoot1 Forward: checkFactor FastBack: central_lib FastForward: involut_lib Up: dmod_lib Top: Singular Manual Contents: Table of Contents Index: Index About: About this document
            User manual for Singular version 3-0-4, Nov 2007, generated by texi2html.