|  |  7.5.4.0. checkFactor Procedure from librarydmod.lib(see  dmod_lib).
 
Example:Usage:
checkFactor(I,f,qs [,eng]); I an ideal, f a poly, qs a poly, eng an optional int
Assume:
checkFactor is called from the basering, created by Sannfs-like proc,
that is, from the Weyl algebra in x1,..,xN,d1,..,dN tensored with K[s].
 The ideal I is the annihilator of f^s in D[s], that is the ideal, computed
 by Sannfs-like procedure (usually called LD there).
 Moreover, f is a polynomial in K[x1,..,xN] and qs is a polynomial in K[s].
 
Return:
int, 1 if qs is a factor of the global Bernstein polynomial of f and 0 otherwise
Purpose:
check whether a univariate polynomial qs is a factor of the
Bernstein-Sato polynomial of f without explicit knowledge of the latter.
 
Note:
If eng <>0, stdis used for Groebner basis computations,otherwise (and by default)
 slimgbis used.
Display:
If printlevel=1, progress debug messages will be printed,
if printlevel>=2, all the debug messages will be printed.
 
 |  | LIB "dmod.lib";
ring r = 0,(x,y),Dp;
poly F = x^4+y^5+x*y^4;
printlevel = 0;
def A = Sannfs(F);
setring A;
poly F = imap(r,F);
checkFactor(LD,F,20*s+31);     // -31/20 is not a root of bs
==> 0
checkFactor(LD,F,20*s+11);     // -11/20 is a root of bs
==> 1
checkFactor(LD,F,(20*s+11)^2); // the multiplicity of -11/20 is 1
==> 0
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