Singular Manual: resolutiongraph

| #### D.6.1.1 resolutiongraph Procedure from library `alexpoly.lib` (see alexpoly_lib). Usage: resolutiongraph(INPUT); INPUT poly or list Assume: INPUT is either a REDUCED bivariate polynomial defining a plane curve singularity, or the output of `hnexpansion(f[,"ess"])`, or the list `hne` in the ring created by `hnexpansion(f[,"ess"])`, or the output of `develop(f)` resp. of `extdevelop(f,n)`, or a list containing the contact matrix and a list of integer vectors with the characteristic exponents of the branches of a plane curve singularity, or an integer vector containing the characteristic exponents of an irreducible plane curve singularity. Return: intmat, the incidence matrix of the resolution graph of the plane curve defined by INPUT, where the entries on the diagonal are the weights of the vertices of the graph and a negative entry corresponds to the strict transform of a branch of the curve. Note: In case the Hamburger-Noether expansion of the curve f is needed for other purposes as well it is better to calculate this first with the aid of `hnexpansion` and use it as input instead of the polynomial itself. If you are not sure whether the INPUT polynomial is reduced or not, use `squarefree(INPUT)` as input instead. Example:
    LIB "alexpoly.lib";
    ring r=0,(x,y),ls;
    poly f1=(y2-x3)^2-4x5y-x7;
    poly f2=y2-x3;
    poly f3=y3-x2;
    resolutiongraph(f1*f2*f3);
    ==> 1,0,1,0,0,0,0,0,1,0,
    ==> 0,2,1,0,0,0,0,0,0,0,
    ==> 1,1,3,0,1,0,0,0,0,0,
    ==> 0,0,0,4,1,0,1,0,0,0,
    ==> 0,0,1,1,5,1,0,0,0,0,
    ==> 0,0,0,0,1,-1,0,0,0,0,
    ==> 0,0,0,1,0,0,-2,0,0,0,
    ==> 0,0,0,0,0,0,0,2,1,0,
    ==> 1,0,0,0,0,0,0,1,3,1,
    ==> 0,0,0,0,0,0,0,0,1,-3
See also: alexanderpolynomial; develop; hnexpansion; totalmultiplicities.

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