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Alberto López Martín

Publications and source records attributed to Alberto López Martín.

6 recordsLinked to original sources

Limit linear series and tropical divisors on chains

We describe the space of Eisenbud-Harris limit linear series on a chain of elliptic curves and compare it with the theory of divisors on tropical chains. Either model allows to compute some invariants of Brill-Noether theory using combinatorial methods. We introduce effective limit linear series.

math.AG↗

Genera of Brill-Noether curves and staircase paths in Young tableaux

In this paper, we compute the genus of the variety of linear series of rank $r$ and degree $d$ on a general curve of genus $g$, with ramification at least $α$ and $β$ at two given points, when that variety is 1-dimensional. Our proof uses degenerations and limit linear series along with an analysis of random staircase paths in Young tableaux, and produces an explicit scheme-theoretic description of the limit linear series of fixed rank and degree on a generic chain of elliptic curves when that scheme is itself a curve.

math.AG↗

Invariants of the Brill-Noether curve

For a projective nonsingular curve of genus $g$, the Brill-Noether locus $W^r_d(C)$ parametrizes line bundles of degree $d$ over $C$ with at least $r+1$ sections. When the curve is generic and the Brill-Noether number $ρ(g,r,d)$ equals $1$, one can then talk of the \emph{Brill-Noether curve}. In this paper, we explore the first two invariants of this curve, giving a new way of calculating the genus of this curve and computing its gonality when $C$ has genus 5.

math.AG↗

Petri map for vector bundles near good bundles

We show that on a generic curve and under some conditions on the degree and genus, there exists a component B of the locus of stable vector bundles of rank r and degree d with at least k sections of the expected dimension such that for a generic vector bundle E of B, the Petri map is injective.

math.AG↗

Virtual normalization and virtual fundamental classes

In this paper, we compare the virtual fundamental classes of the stacks of $(g,β,μ)$-stable ramified maps $\bar{\mathfrak U}_{g,μ}(X,β)$ and of $(g,β,μ)$-log stable ramified maps $\bar{\mathfrak U}^{\mathrm{log}}_{g,μ}(X,β)$. For that we will see how they are identified via virtual normalization and then apply Costello's push-forward formula.

math.AG↗