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Related papers: Welschinger--Witt invariants

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We compute the purely real Welschinger invariants, both original and modified, for all real del Pezzo surfaces of degree at least 2. We show that under some conditions, for such a surface $X$ and a real nef and big divisor class $D$,…

Algebraic Geometry · Mathematics 2018-01-18 Ilia Itenberg , Viatcheslav Kharlamov , Eugenii Shustin

Let $S$ be a smooth del Pezzo surface over a field $k$ of characteristic $\neq 2, 3$. We define an invariant in the Grothendieck-Witt ring $GW(k)$ for "counting" rational curves in a curve class $D$ of fixed positive degree (with respect to…

Algebraic Geometry · Mathematics 2018-08-08 Marc Levine

We introduce enumerative invariants of real del Pezzo surfaces that count real rational curves belonging to a given divisor class, passing through a generic conjugation-invariant configuration of points and satisfying preassigned tangency…

Algebraic Geometry · Mathematics 2016-08-09 Eugenii Shustin

The Welschinger invariants of real rational algebraic surfaces count real rational curves which represent a given divisor class and pass through a generic conjugation-invariant configuration of points. No invariants counting real curves of…

Algebraic Geometry · Mathematics 2014-09-23 Eugenii Shustin

We give a recursive formula for purely real Welschinger invariants of real Del Pezzo surfaces of degree $K^2\ge 3$, where in the case of surfaces of degree $3$ with two real components we introduce a certain modification of Welschinger…

Algebraic Geometry · Mathematics 2015-01-07 Ilia Itenberg , Viatcheslav Kharlamov , Eugenii Shustin

The Welschinger numbers, a kind of a real analog of the Gromov-Witten numbers which count the complex rational curves through a given generic collection of points, bound from below the number of real rational curves for any real generic…

Algebraic Geometry · Mathematics 2015-06-26 I. Itenberg , V. Kharlamov , E. Shustin

Quadratic Gromov--Witten invariants allow one to obtain an arithmetically meaningful count of curves satisfying constraints over a field $k$ without assuming that $k$ is the field of complex or real numbers. This paper studies the behavior…

Algebraic Geometry · Mathematics 2025-06-24 Erwan Brugallé , Kirsten Wickelgren

We give a recursive formula for purely real Welschinger invariants of the following real Del Pezzo surfaces: the projective plane blown up at $q$ real and $s \leq 1$ pairs of conjugate imaginary points, where $q+2s\le 5$, and the real…

Algebraic Geometry · Mathematics 2011-08-11 Ilia Itenberg , Viatcheslav Kharlamov , Eugenii Shustin

The Welschinger invariants of real rational algebraic surfaces are natural analogues of the Gromov-Witten invariants, and they estimate from below the number of real rational curves passing through prescribed configurations of points. We…

Algebraic Geometry · Mathematics 2007-05-23 E. Shustin

The Welschinger invariants of real rational algebraic surfaces are natural analogues of the genus zero Gromov-Witten invariants. We establish a tropical formula to calculate the Welschinger invariants of real toric Del Pezzo surfaces for…

Algebraic Geometry · Mathematics 2008-03-02 E. Shustin

We define a quadratically enriched count of rational curves in a given divisor class passing through a collection of points on a del Pezzo surface $S$ of degree $\geq 3$ over a perfect field $k$ of characteristic $\neq 2,3.$ When $S$ is…

Algebraic Geometry · Mathematics 2026-03-03 Jesse Leo Kass , Marc Levine , Jake P. Solomon , Kirsten Wickelgren

We establish the enumerativity of (original and modified) Welschinger invariants for every real divisor on any real algebraic Del Pezzo surface and give an algebro-geometric proof of the invariance of that count both up to variation of the…

Algebraic Geometry · Mathematics 2017-05-04 Ilia Itenberg , Viatcheslav Kharlamov , Eugenii Shustin

The invariance of the Welschinger numbers for real unnodal Del Pezzo surfaces, which we used for the enumeration of real rational curves on real toric Del Pezzo surfaces (see math.AG/0303378 and IMRN 49 (2003), 2639-2653), follows from…

Algebraic Geometry · Mathematics 2007-05-23 Ilia Itenberg , Viatcheslav Kharlamov , Eugenii Shustin

We introduce Gromov-Witten invariants with naive tangency conditions at the marked points of the source curve. We then establish an explicit formula which expresses Gromov-Witten invariants with naive tangency conditions in terms of…

Algebraic Geometry · Mathematics 2023-10-23 Felix Janda , Tony Yue Yu

Welschinger's invariant bounds from below the number of real rational curves through a given generic collection of real points in the real projective plane. We estimate this invariant using Mikhalkin's approach which deals with a…

Algebraic Geometry · Mathematics 2007-05-23 I. Itenberg , V. Kharlamov , E. Shustin

This is an overview of some of the invariants that were discovered by Welschinger in the context of enumerative real algebraic geometry. Their definition finds a natural setup in real symplectic geometry. In particular, they can be studied…

Symplectic Geometry · Mathematics 2011-10-26 Alexandru Oancea

We continue our quest for real enumerative invariants not sensitive to changing the real structure and extend the construction we uncovered previously for counting curves of anti-canonical degree $\leqslant 2$ on del Pezzo surfaces with…

Algebraic Geometry · Mathematics 2026-03-18 Sergey Finashin , Viatcheslav Kharlamov

Inspired by M-theory and superconformal field theory, we extend the notions of local Gromov-Witten invariants from the case of del Pezzo surfaces to shrinkable surfaces, a class of reducible surfaces with simple normal crossings satisfying…

Algebraic Geometry · Mathematics 2023-09-13 Sheldon Katz , Sungwoo Nam

In this paper, we establish formulas for computing genus-$0$ Gromov-Witten and Welschinger invariants of some del Pezzo varieties of dimension three by comparing to that of dimension two. These formulas are generalizations of that given in…

Algebraic Geometry · Mathematics 2026-05-27 Thi-Ngoc-Anh Nguyen

We construct positive-genus analogues of Welschinger's invariants for many real symplectic manifolds, including the odd-dimensional projective spaces and the renowned quintic threefold. In some cases, our invariants provide lower bounds for…

Symplectic Geometry · Mathematics 2018-02-27 Penka Georgieva , Aleksey Zinger
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