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D.6.7.5 monodromy

Procedure from library gmssing.lib (see gmssing_lib).

Usage:
monodromy(t); poly t

Assume:
characteristic 0; local degree ordering;
isolated critical point 0 of t

Return:
 
list l;  Jordan data jordan(M) of monodromy matrix exp(-2*pi*i*M)
  ideal l[1];
    number l[1][i];  eigenvalue of i-th Jordan block of M
  intvec l[2];
    int l[2][i];  size of i-th Jordan block of M
  intvec l[3];
    int l[3][i];  multiplicity of i-th Jordan block of M

Example:
 
LIB "gmssing.lib";
ring R=0,(x,y),ds;
poly t=x5+x2y2+y5;
monodromy(t);
==> [1]:
==>    _[1]=1/2
==>    _[2]=7/10
==>    _[3]=9/10
==>    _[4]=1
==>    _[5]=11/10
==>    _[6]=13/10
==> [2]:
==>    2,1,1,1,1,1
==> [3]:
==>    1,2,2,1,2,2
See also: linalg_lib; mondromy_lib.