469 citations
Counting papers with at most 25 authors, so collaboration author lists do not stand in for the people here.
- Centre for Arctic Gas Hydrate, Environment and ClimateNO44 papers
- Centre National de la Recherche ScientifiqueFR28 papers
- University of OsloNO21 papers
- Norwegian Computing CenterNO16 papers
- University of WarwickGB13 papers
- University of ArizonaUS12 papers
- Technical University of DenmarkDK11 papers
- KTH Royal Institute of TechnologySE10 papers
- Massachusetts Institute of TechnologyUS10 papers
- Norwegian University of Science and TechnologyNO10 papers
- Observatoire de ParisFR10 papers
- University Hospital of North NorwayNO10 papers
52 papers · 1 filter
Weyl metrizability of 3-dimensional projective structures and CR submanifolds
Omid Makhmali
A projective structure is Weyl metrizable if it has a representative that preserves a conformal structure. We interpret Weyl metrizability of 3-dimensional projective structures as…
Variationality of conformal geodesics in dimension 3
Boris Kruglikov, Vladimir S. Matveev, Wijnand Steneker
Conformal geodesics form an invariantly defined family of unparametrized curves in a conformal manifold generalizing unparametrized geodesics/paths of projective connections. The e…
Invariant divisors and equivariant line bundles
Boris Kruglikov, Eivind Schneider
Scalar relative invariants play an important role in the theory of group actions on a manifold as their zero sets are invariant hypersurfaces. Relative invariants are central in ma…
Lie Admissible Triple Algebras: The Connection Algebra of Symmetric Spaces
Hans Munthe-Kaas, Jonatan Stava
Associated to a symmetric space there is a canonical connection with zero torsion and parallel curvature. This connection acts as a binary operator on the vector space of smooth se…
Parabolic quasi-contact cone structures with an infinitesimal symmetry
Omid Makhmali, Katja Sagerschnig
We interpret the property of having an infinitesimal symmetry as a variational property in certain geometric structures. This is achieved by establishing a one-to-one correspondenc…
On Uniqueness of Submaximally Symmetric Vector Ordinary Differential Equations of C-Class
Johnson Allen Kessy, Dennis The
The fundamental invariants for vector ODEs of order considered up to point transformations consist of generalized Wilczynski invariants and C-class invariants. An ODE of C-…
Exceptionally simple super-PDE for
Andrea Santi, Dennis The
For the largest exceptional simple Lie superalgebra , having dimension , we provide two explicit geometric realizations as supersymmetries, namely as the symmetry su…
Recurrent Lorentzian Weyl spaces
Andrei Dikarev, Anton S. Galaev, Eivind Schneider
We find the local form of all non-closed Lorentzian Weyl manifolds with recurrent curvature tensor.If the dimension of the manifold is greater than 3, then the confo…
Almost every path structure is not variational
Boris S. Kruglikov, Vladimir S. Matveev
Given a smooth family of unparameterized curves such that through every point in every direction there passes exactly one curve, does there exist a Lagrangian with extremals being…
Symmetry gaps for higher order ordinary differential equations
Johnson Allen Kessy, Dennis The
The maximal contact symmetry dimensions for scalar ODEs of order and vector ODEs of order are well known. Using a Cartan-geometric approach, we determine for these…
Differential invariants of Kundt spacetimes
Boris Kruglikov, Eivind Schneider
We find generators for the algebra of rational differential invariants for general and degenerate Kundt spacetimes and relate this to other approaches to the equivalence problem fo…
Second-order PDEs in 4D with half-flat conformal structure
Sobhi Berjawi, Eugene Ferapontov, Boris Kruglikov +1
We study second-order PDEs in 4D for which the conformal structure defined by the characteristic variety of the equation is half-flat (self-dual or anti-self-dual) on every solutio…
Projectable Lie algebras of vector fields in 3D
Eivind Schneider
Starting with Lie's classification of finite-dimensional transitive Lie algebras of vector fields on we construct Lie algebras of vector fields on the bundle $\mathbb…
Differential invariants of Einstein-Weyl structures in 3D
Boris Kruglikov, Eivind Schneider
Einstein-Weyl structures on a three-dimensional manifold is given by a system of PDEs on sections of a bundle over . This system is invariant under the Lie pseudogroup $…
Homogeneous Levi non-degenerate hypersurfaces in
Boris Doubrov, Alexandr Medvedev, Dennis The
We classify all (locally) homogeneous Levi non-degenerate real hypersurfaces in with symmetry algebra of dimension .
On C-class equations
Andreas Cap, Boris Doubrov, Dennis The
The concept of a C-class of differential equations goes back to E. Cartan with the upshot that generic equations in a C-class can be solved without integration. While Cartan's defi…
Erratum to: Almost complex structures in 6D with non-degenerate Nijenhuis tensors and large symmetry groups
Boris Kruglikov, Henrik Winther
We correct an error in the second part of Theorem 3 of our original paper (arXiv:1512.07161).
Non-degenerate Para-Complex Structures in 6D with Large Symmetry Groups
Boris Kruglikov, Henrik Winther
For an almost product structure on a manifold of dimension with non-degenerate Nijenhuis tensor , we show that the automorphism group has dimension at…
Invariant connections and -Einstein structures on isotropy irreducible spaces
Ioannis Chrysikos, Christian O'Cadiz Gustad, Henrik Winther
This paper is devoted to a systematic study and classification of invariant affine or metric connections on certain classes of naturally reductive spaces. For any non-symmetric, ef…
Differential Invariants of Self-Dual conformal structures
Boris Kruglikov, Eivind Schneider
We compute the quotient of the self-duality equation for conformal metrics by the action of the diffeomorphism group. We also determine Hilbert polynomial, counting the number of i…
Conformal Differential Invariants
Boris Kruglikov
We compute the Hilbert polynomial and the Poincare function counting the number of fixed jet-order differential invariants of conformal metric structures modulo local diffeomorphis…
Jet-determination of symmetries of parabolic geometries
Boris Kruglikov, Dennis The
We establish 2-jet determinacy for the symmetry algebra of the underlying structure of any (complex or real) parabolic geometry. At non-flat points, we prove that the symmetry alge…
Exceptionally simple PDE
Dennis The
We give local descriptions of parabolic contact structures and show how their flat models yield explicit PDE having symmetry algebras isomorphic to all complex simple Lie algebras…
Veronese webs and nonlinear PDEs
Boris Kruglikov, Andriy Panasyuk
Veronese webs are closely related to bi-Hamiltonian systems, as was shown by Gelfand and Zakharevich. Recently a correspondence between Veronese three-dimensional webs and three-di…