|  |  7.5.4.0. checkRoot Procedure from librarydmod.lib(see  dmod_lib).
 
Example:Usage:
checkRoot(f,alpha [,S,eng]); poly f, number alpha, string S, int eng
Return:
int
Assume:
Basering is a commutative ring, alpha is a positive rational number.
Purpose:
check whether a negative rational number -alpha is a root of the global
Bernstein-Sato polynomial of f and compute its multiplicity,
 with the algorithm given by S and with the Groebner basis engine given by eng.
 
Note:
The annihilator of f^s in D[s] is needed and hence it is computed with the
algorithm by Briancon and Maisonobe. The value of a string S can be
 'alg1' (default) - for the algorithm 1 of [LM08]
 'alg2' - for the algorithm 2 of [LM08]
 Depending on the value of S, the output of type int is:
 'alg1': 1 only if -alpha is a root of the global Bernstein-Sato polynomial
 'alg2': the multiplicity of -alpha as a root of the global Bernstein-Sato
 polynomial of f. If -alpha is not a root, the output is 0.
 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";
printlevel=0;
ring r = 0,(x,y),Dp;
poly F = x^4+y^5+x*y^4;
checkRoot(F,11/20);    // -11/20 is a root of bf
==> 1
poly G = x*y;
checkRoot(G,1,"alg2"); // -1 is a root of bg with multiplicity 2
==> 2
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