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D.5.9.1 intersectionDiv
Procedure from library reszeta.lib (see reszeta_lib).
- Usage:
- intersectionDiv(L);
L = list of rings
- Assume:
- L is output of resolution of singularities
(only case of isolated surface singularities)
- Compute:
- intersection matrix and genera of the exceptional divisors
(considered as curves on the strict transform)
- Return:
- list l, where
l[1]: intersection matrix of exceptional divisors
l[2]: intvec, genera of exceptional divisors
l[3]: divisorList, encoding the identification of the divisors
Example:
| | LIB "reszeta.lib";
ring r = 0,(x(1..3)),dp(3);
ideal J=x(3)^5+x(2)^4+x(1)^3+x(1)*x(2)*x(3);
list re=resolve(J);
list di=intersectionDiv(re);
di;
==> [1]:
==> -3,1,1,
==> 1,-4,1,
==> 1,1,-2
==> [2]:
==> 0,0,0
==> [3]:
==> [1]:
==> [1]:
==> 3,1,1
==> [2]:
==> 5,1,1
==> [2]:
==> [1]:
==> 3,1,2
==> [2]:
==> 4,1,1
==> [3]:
==> 5,1,2
==> [3]:
==> [1]:
==> 4,2,1
==> [2]:
==> 5,2,1
==> [4]:
==> 1,1,1
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