scholarly journals A computational approach to the ample cone of moduli spaces of curves

2018 ◽  
Vol 28 (01) ◽  
pp. 37-51
Author(s):  
Claudio Fontanari ◽  
Riccardo Ghiloni ◽  
Paolo Lella

We present an alternate proof, much quicker and more straightforward than the original one, of the celebrated F-conjecture on the ample cone of the moduli space [Formula: see text] of stable rational curves with [Formula: see text] marked points in the case [Formula: see text].

2020 ◽  
Vol 8 ◽  
Author(s):  
RENZO CAVALIERI ◽  
MELODY CHAN ◽  
MARTIN ULIRSCH ◽  
JONATHAN WISE

We contribute to the foundations of tropical geometry with a view toward formulating tropical moduli problems, and with the moduli space of curves as our main example. We propose a moduli functor for the moduli space of curves and show that it is representable by a geometric stack over the category of rational polyhedral cones. In this framework, the natural forgetful morphisms between moduli spaces of curves with marked points function as universal curves. Our approach to tropical geometry permits tropical moduli problems—moduli of curves or otherwise—to be extended to logarithmic schemes. We use this to construct a smooth tropicalization morphism from the moduli space of algebraic curves to the moduli space of tropical curves, and we show that this morphism commutes with all of the tautological morphisms.


1996 ◽  
Vol 07 (02) ◽  
pp. 151-181 ◽  
Author(s):  
YI HU

We expose in detail the principle that the relative geometric invariant theory of equivariant morphisms is related to the GIT for linearizations near the boundary of the G-effective ample cone. We then apply this principle to construct and reconstruct various universal moduli spaces. In particular, we constructed the universal moduli space over [Formula: see text] of Simpson’s p-semistable coherent sheaves and a canonical rational morphism from the universal Hilbert scheme over [Formula: see text] to a compactified universal Picard.


2004 ◽  
Vol 15 (01) ◽  
pp. 13-45 ◽  
Author(s):  
ANA-MARIA CASTRAVET

Let C be a smooth projective complex curve of genus g≥2 and let M be the moduli space of rank 2, stable vector bundles on C, with fixed determinant of degree 1. For any k≥1, we find all the irreducible components of the space of rational curves on M, of degree k. In particular, we find the maximal rationally connected fibrations of these components. We prove that there is a one-to-one correspondence between moduli spaces of rational curves on M and moduli spaces of rank 2 vector bundles on ℙ1×C.


Author(s):  
Markus Reineke ◽  
Thorsten Weist

Abstract We identify certain Gromov–Witten invariants counting rational curves with given incidence and tangency conditions with the Euler characteristics of moduli spaces of point configurations in projective spaces. On the Gromov–Witten side, S. Fomin and G. Mikhalkin established a recurrence relation via tropicalization, which is realized on the moduli space side using Donaldson–Thomas invariants of subspace quivers.


Author(s):  
Maxim E. Kazaryan ◽  
Sergei K. Lando ◽  
Victor V. Prasolov

2020 ◽  
Vol Volume 4 ◽  
Author(s):  
Rahul Pandharipande ◽  
Johannes Schmitt

While the Chow groups of 0-dimensional cycles on the moduli spaces of Deligne-Mumford stable pointed curves can be very complicated, the span of the 0-dimensional tautological cycles is always of rank 1. The question of whether a given moduli point [C,p_1,...,p_n] determines a tautological 0-cycle is subtle. Our main results address the question for curves on rational and K3 surfaces. If C is a nonsingular curve on a nonsingular rational surface of positive degree with respect to the anticanonical class, we prove [C,p_1,...,p_n] is tautological if the number of markings does not exceed the virtual dimension in Gromov-Witten theory of the moduli space of stable maps. If C is a nonsingular curve on a K3 surface, we prove [C,p_1,...,p_n] is tautological if the number of markings does not exceed the genus of C and every marking is a Beauville-Voisin point. The latter result provides a connection between the rank 1 tautological 0-cycles on the moduli of curves and the rank 1 tautological 0-cycles on K3 surfaces. Several further results related to tautological 0-cycles on the moduli spaces of curves are proven. Many open questions concerning the moduli points of curves on other surfaces (Abelian, Enriques, general type) are discussed. Comment: Published version


2019 ◽  
Vol 155 (5) ◽  
pp. 833-862 ◽  
Author(s):  
Brian Lehmann ◽  
Sho Tanimoto

Let$X$be a smooth projective Fano variety over the complex numbers. We study the moduli space of rational curves on$X$using the perspective of Manin’s conjecture. In particular, we bound the dimension and number of components of spaces of rational curves on$X$. We propose a geometric Manin’s conjecture predicting the growth rate of a counting function associated to the irreducible components of these moduli spaces.


2017 ◽  
Vol 28 (12) ◽  
pp. 1750090 ◽  
Author(s):  
Hayato Saito

In this paper, we prove formulas that represent two-pointed Gromov–Witten invariant [Formula: see text] of projective hypersurfaces with [Formula: see text] in terms of Chow ring of [Formula: see text], the moduli spaces of stable maps from genus [Formula: see text] stable curves to projective space [Formula: see text]. Our formulas are based on representation of the intersection number [Formula: see text], which was introduced by Jinzenji, in terms of Chow ring of [Formula: see text], the moduli space of quasi maps from [Formula: see text] to [Formula: see text] with two marked points. In order to prove our formulas, we use the results on Chow ring of [Formula: see text], that were derived by Mustaţǎ and Mustaţǎ. We also present explicit toric data of [Formula: see text] and prove relations of Chow ring of [Formula: see text].


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