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D.6.1.9 charexp2inter

Procedure from library alexpoly.lib (see alexpoly_lib).

Usage:
charexp2inter(contact,charexp), contact matrix, charexp list

Assume:
charexp contains the integer vectors of characteristic exponents of the branches of a plane curve singularity, and contact is their contact matrix

Return:
intmat, the matrix intersection multiplicities of the branches

Example:
 
LIB "alexpoly.lib";
ring r=0,(x,y),ds;
list INV=invariants((x2-y3)*(x3-y2)*((x2-y3)^2-4x5y-x7));
intmat contact=INV[4][1];
list charexp=INV[1][1],INV[2][1],INV[3][1];
// The intersection matrix is INV[4][2].
print(INV[4][2]);
==>      0     4     8
==>      4     0    17
==>      8    17     0
// And it is calulated as ...
print(charexp2inter(contact,charexp));
==>      0     4     8
==>      4     0    17
==>      8    17     0
See also: invariants; resolutiongraph; semigroup; totalmultiplicities.