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Related papers: Welschinger invariants revisited

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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 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

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

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

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 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

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

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

We collect in this note some observations about original Welschinger invariants of real symplectic fourfolds. None of their proofs is difficult, nevertheless these remarks do not seem to have been made before. Our main result is that when…

Algebraic Geometry · Mathematics 2020-01-07 Erwan Brugallé

Welschinger invariants are signed counts of real rational curves satisfying contraints. Quadratic Gromov--Witten invariants give such counts over general fields of characteristic different from 2 and 3. For rational del Pezzo surfaces over…

Algebraic Geometry · Mathematics 2025-09-05 Erwan Brugallé , Johannes Rau , Kirsten Wickelgren

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

We prove new local inequality for divisors on surfaces and utilize it to compute $\alpha$-invariants of singular del Pezzo surfaces, which implies that del Pezzo surfaces of degree one whose singular points are of type $\mathbb{A}_{1}$,…

Algebraic Geometry · Mathematics 2012-10-04 Ivan Cheltsov , Dimitra Kosta

We suggest an invariant way to enumerate nodal and nodal-cuspidal real deformations of real plane curve singularities. The key idea is to assign Welschinger signs to the counted deformations. Our invariants can be viewed as a local version…

Algebraic Geometry · Mathematics 2019-07-02 Eugenii 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

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 define a series of relative tropical Welschinger-type invariants of real toric surfaces. In the Del Pezzo case, these invariants can be seen as real tropical analogs of relative Gromov-Witten invariants, and are subject to a recursive…

Algebraic Geometry · Mathematics 2009-01-20 Ilia Itenberg , Viatcheslav Kharlamov , Eugenii Shustin

We generalize Block-G\"ottsche polynomials, originally defined for toric del Pezzo surfaces, to arbitrary surfaces. To do this, we show that these polynomials arise as special cases of BPS polynomials, defined for any surface $S$ as Laurent…

Algebraic Geometry · Mathematics 2025-06-04 Hülya Argüz , Pierrick Bousseau

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

We estimate $\delta$-invariants of some singular del Pezzo surfaces with quotient singularities, which we studied ten years ago. As a result, we show that each of these surfaces admits an orbifold K\"ahler--Einstein metric.

Algebraic Geometry · Mathematics 2020-01-22 Ivan Cheltsov , Jihun Park , Constantin Shramov
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