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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 calculated as ...
print(charexp2inter(contact,charexp));
==> 0 4 8
==> 4 0 17
==> 8 17 0
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See also:
invariants;
resolutiongraph;
semigroup;
totalmultiplicities.
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