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arXiv · 1810.03926

Harbourne constants, pull-back clusters and ramified morphisms

Piotr Pokora·Joaquim Roé
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Abstract

We describe the effect of ramified morphisms on Harbourne constants of reduced effective divisors. With this goal, we introduce the pullback of a weighted cluster of infinitely near points under a dominant morphism between surfaces, and describe some of its basic properties. As an application, we describe configurations of curves with transversal intersections and $H$-index arbitarily close to $-25/7\simeq -3.571$, smaller than any previously known result.

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Piotr Pokora, Joaquim Roé. 2018-10-09. Harbourne constants, pull-back clusters and ramified morphisms. https://doi.org/10.1007/s00025-019-1031-x

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