activity
20092026
most citedA complete normal form for everywhere Levi degenerate hypersurfaces in

3 citations · 17 across the 20 of their papers we have counts for

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24 papers · 1 filter

math.CV2026

Strong Ramadanov Conjecture for Real Ellipsoids in : two approaches

Jan Gregorovic, Ilya Kossovskiy, Son-Ying Li +1

In this paper, we provide two (significantly different) proofs of the well known Strong Ramadanov Conjecture for the class of real ellipsoids in the complex -space.

math.CV2025

Sphericity and Analyticity of a strictly pdeusoconvex hypersurface in low regularity I

Ilya Kossovskiy, Dmitri Zaitsev

In our earlier work \cite{KZ}, we introduced an analytic regularizability theory for smooth strictly pseudoconvex hypersurfaces in complex space. That is, we found a necessary and…

math.CV2025

On the regularity of nondegenerate hypo-analytic structures of hypersurface type

Ilya Kossovskiy, Vinícius Novelli

For a smooth, non-degenerate locally integrable structure of hypersurface type on a manifold , we provide necessary and sufficient conditions for it to be equivalent, near a poi…

math.CV2024

Holomorphic vector fields with real integral manifolds

Martin Kolář, Ilya Kossovskiy, Bernhard Lamel

We classify singular holomorphic vector fields in two-dimensional complex space admitting a (Levi-nonflat) real-analytic invariant 3-fold through the singularity. In this way, we c…

math.CV2024

The jet transcendence degree of a real hypersurface and Huang-Ji-Yau Conjecture

Jan Gregorovic, Ilya Kossovskiy

We investigate the problem of holomorphic algebraizibility for real hypersurfaces in complex space. We introduce a new invariant of a (real-analytic) Levi-nondegenerate hypersurfac…

math.CV2023★ 1 cited

New examples of -nondegenerate real hypersurfaces in with arbitrary nilpotent symbols

Martin Kolář, Ilya Kossovskiy, David Sykes

We introduce a class of uniformly -nondegenerate CR hypersurfaces in , for , having a rank Levi kernel. The class is first of all remarkable by the fact t…

math.CV2020

Regularity of CR-mappings between Fuchsian type hypersurfaces in

P. Ebenfelt, I. Kossovskiy, B. Lamel

We investigate regularity of CR-mappings between real-analytic infinite type hypersurfaces in . We show that, under the Fuchsian type condition, all (respectively form…

math.CV2019★ 3 cited

Classification of homogeneous strictly pseudoconvex hypersurfaces in

Ilya Kossovskiy, Alexander Loboda

Locally homogeneous strictly pseudoconvex hypersurfaces in were classified by E.\,Cartan in 1932. In this work, we complete the classification of locally homogeneous…

math.CV2019

Real-analytic coordinates for smooth strictly pseudoconvex CR-structures

Ilya Kossovskiy, Dmitri Zaitsev

For a smooth strictly pseudoconvex hypersurface in a complex manifold, we give a necessary and sufficient condition for being CR-diffeomorphic to a real-analytic CR manifold. Our c…

math.CV2019★ 3 cited

A complete normal form for everywhere Levi degenerate hypersurfaces in

Martin Kolar, Ilya Kossovskiy

-nondegenerate real hypersurfaces in complex manifolds play an important role in CR-geometry and the theory of Hermitian Symmetric Domains. In this paper, we construct a complet…

math.CV2018

The equivalence theory for infinite type hypersurfaces in

Peter Ebenfelt, Ilya Kossovskiy, Bernhard Lamel

We develop a classification theory for real-analytic hypersurfaces in in the case when the hypersurface is of {\em infinite type} at the reference point. This is the…

math.CV2016★ 3 cited

Equivalence of Cauchy-Riemann manifolds and multisummability theory

Ilya Kossovskiy, Bernhard Lamel, Laurent Stolovitch

We prove that if two real-analytic hypersurfaces in are equivalent formally, then they are also CR-equivalent at the respective point. As a corollary, we p…

math.CV2016★ 3 cited

Regularity of CR-mappings into Levi-degenerate hypersurfaces

Ilya Kossovskiy, Bernhard Lamel, Ming Xiao

We provide regularity results for CR-maps between real hypersurfaces in complex spaces of different dimension with a Levi-degenerate target. We address both the real-analytic and t…

math.CV2016

Normal forms in Cauchy-Riemann Geometry: a survey

Martin Kolar, Ilya Kossovskiy, Dmitri Zaitsev

One of effective ways to solve the equivalence problem and describe moduli spaces for real submanifolds in complex space is the normal form approach. In this survey, we outline som…

math.CV2015

Sphericity of a real hypersurface via projective geometry

Ilya Kossovskiy

In this work, we obtain an unexpected geometric characterization of sphericity of a real-analytic Levi-nondegenerate hypersurface . We prove that is sphe…

math.CV2015

On the embeddability of real hypersurfaces into hyperquadrics

Ilya Kossovskiy, Ming Xiao

In this paper, we provide {\em effective} results on the non-embeddability of real-analytic hypersurfaces into a hyperquadric. We show that, for any , the defining fun…

math.CV2015★ 2 cited

New extension phenomena for solutions of tangential Cauchy\,-\,Riemann Equations

Ilya Kossovskiy, Bernhard Lamel

In our recent work [25] we showed that CR-diffeomorphisms of real-analytic Levi-nonflat hypersurfaces in are not analytic in general. This result raised…

math.CV2014

Convergent normal form and canonical connection for hypersurfaces of finite type in

Ilya Kossovskiy, Dmitri Zaitsev

We study the holomorphic equivalence problem for finite type hypersurfaces in . We discover a geometric condition, which is sufficient for the existence of a natural c…

math.CV2014

On the analyticity of CR-diffeomorphisms

Ilya Kossovskiy, Bernhard Lamel

In any positive CR-dimension and CR-codimension we provide a construction of real-analytic holomorphically nondegenerate CR-submanifolds, which are CR-equivalent, but ar…

math.CV2014

Convergent normal form for real hypersurfaces at generic Levi degeneracy

Ilya Kossovskiy, Dmitri Zaitsev

We construct a complete convergent normal form for a real hypersurface in $\CC{N},\,N\geq 2$ at generic Levi degeneracy. This seems to be the first convergent normal form for a Lev…

math.CV2014

Analytic Differential Equations and Spherical Real Hypersurfaces

Ilya Kossovskiy, Rasul Shafikov

We establish an injective correspondence between real-analytic nonminimal hypersurfaces , spherical at a generic point, and…

math.CV2012★ 2 cited

Analytic Continuation of Holomorphic Mappings From Non-minimal Hypersurfaces

I. Kossovskiy, R. Shafikov

We study the analytic continuation problem for a germ of a biholomorphic mapping from a non-minimal real hypersurface $M\subset\CC{n}$ into a real hyperquadric $\mathcal Q\subset\C…

math.CV2009

Classification of homogeneous CR-manifolds in dimension 4

V. K. Beloshapka, I. G. Kossovskiy

Locally homogeneous CR-manifolds in dimension 3 were classified, up to local CR-equivalence, by E.Cartan. We classify, up to local CR-equivalence, all locally homogeneous CR-manifo…

math.CV2009

Continuation of CR-Automorphisms of Levi Degenerate Hyperquadrics to the Projective Space

A. V. Isaev, I. G. Kossovskiy

We show that every CR-automorphism of the closure of a Levi degenerate hyperquadric in the projective space extends to a holomorphic automorphism of the projective space.