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Related papers: Singular Welschinger invariants

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We study a specific class of deformations of curve singularities: the case when the singular point splits to several ones, such that the total $\delta$ invariant is preserved. These are also known as equi-normalizable or equi-generic…

Algebraic Geometry · Mathematics 2010-01-18 Dmitry Kerner

We define a signed count of real rational pseudo-holomorphic curves appearing in a one-parameter family of real Spin symplectic K3 surfaces. We show that this count is an invariant of the deformation class of the family. In the case of a…

Symplectic Geometry · Mathematics 2015-04-17 Crétois Rémi

We define refined invariants which "count" nodal curves in sufficiently ample linear systems on surfaces, conjecture that their generating function is multiplicative, and conjecture explicit formulas in the case of K3 and abelian surfaces.…

Algebraic Geometry · Mathematics 2015-09-01 Lothar Göttsche , Vivek Shende

We give examples of real enumerative problems without real solutions. Most of the examples concern rational curves in ${\mathbb C}{\mathbb P}^3$ passing through a real set of points and lines.

Algebraic Geometry · Mathematics 2014-01-13 János Kollár

We investigate geometric invariants of cuspidal edges on focal surfaces of regular surface. In particular, we shall clarify the sign of the singular curvature at a cuspidal edge on a focal surface using singularities of parallel surface of…

Differential Geometry · Mathematics 2026-05-19 Keisuke Teramoto

In this survey on local additive invariants of real and complex definable singular germs we systematically present classical or more recent invariants of different nature as emerging from a tame degeneracy principle. For this goal, we…

Algebraic Geometry · Mathematics 2013-11-01 Georges Comte

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

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 construct invariants under deformation of real symplectic 4-manifolds. These invariants are obtained by counting three different kinds of real rational J-holomorphic curves which realize a given homology class and pass through a given…

Symplectic Geometry · Mathematics 2007-05-23 Jean-Yves Welschinger

We use a knot invariant, namely the Tristram--Levine signature to study deformations of singular points of plane curves. We find a bound on the sum of M numbers over all singularities of a generic fiber in terms of the M number of the…

Algebraic Geometry · Mathematics 2009-09-24 Maciej Borodzik

We introduce new invariants of a class of toric surfaces (including the projective plane) that arise from appropriate enumeration of real curves of genus one and two. These invariants admit a refinement similar to the one introduced by…

Algebraic Geometry · Mathematics 2025-04-22 Ilia Itenberg , Eugenii Shustin

In this paper, we study polar quotients and \L ojasiewicz exponents of plane curve singularities, which are {\em not necessarily reduced}. We first show that the polar quotients is a topological invariant. We next prove that the \L…

Algebraic Geometry · Mathematics 2020-01-31 Hong-Duc Nguyen , Tien-Son Pham , Phi-Dung Hoang

Consider a smooth projective curve and a given embedding into projective space via a sufficiently positive line bundle. We can form the secant variety of $k$-planes through the curve. These are singular varieties, with each secant variety…

Algebraic Geometry · Mathematics 2024-10-15 Daniel Brogan

We show the possible Milnor numbers of deformations of semi-quasi-homogeneous isolated plane curve singularities. In Theorem 1.1 we list integers can be attained as Milnor numbers of a given semi-quasi-homogeneous singularity.

Algebraic Geometry · Mathematics 2016-08-15 Maria Michalska , Justyna Walewska

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 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

In this paper, we consider deformations of singular complex curves on complex surfaces. Despite the fundamental nature of the problem, little seems to be known for curves on general surfaces. Let $C\subset S$ be a complete integral curve on…

Algebraic Geometry · Mathematics 2023-10-24 Takeo Nishinou

In this note we compute some enumerative invariants of real and complex projective spaces by means of some enriched graphs called floor diagrams.

Algebraic Geometry · Mathematics 2007-06-04 Erwan Brugallé , Grigory Mikhalkin

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 conjectural formula for the characteristic number of rational cuspidal curves in the projective plane by extending the idea of Kontsevich's recursion formula (namely, pulling back the equality of two divisors in the four pointed…

Algebraic Geometry · Mathematics 2025-04-03 Indranil Biswas , Apratim Choudhury , Ritwik Mukherjee , Anantadulal Paul