Real Zeuthen numbers for two lines

dc.creatorBertrand, Benoit
dc.date2007-10-04
dc.date.accessioned2026-07-07T08:34:18Z
dc.date.available2026-07-07T08:34:18Z
dc.descriptionGiven three natural numbers $k,l,d$ such that $k+l=d(d+3)/2$, the Zeuthen number $N_{d}(l)$ is the number of nonsingular complex algebraic curves of degree $d$ passing through $k$ points and tangent to $l$ lines in $\PP^2$. It does not depend on the generic configuration $C$ of points and lines chosen. If the points and lines are real, the corresponding number $N_{d}^\RR(l,C)$ of real curves usually depends on the configuration chosen. We use Mikhalkin's tropical correspondence theorem to prove that for two lines the real Zeuthen problem is maximal: there exists a configuration $C$ such that $N_{d}^\RR(2,C)=N_{d}(2)$. The correspondence theorem reduces the computation to counting certain lattice paths with multiplicities.
dc.description6 pages, 3 figures
dc.identifierhttps://arxiv.org/abs/0710.1095
dc.identifierhttp://arxiv.org/abs/0710.1095
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/139390
dc.subjectAlgebraic Geometry
dc.subject14P99; 14N10
dc.titleReal Zeuthen numbers for two lines
dc.typetext

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