Zobrazeno 1 - 10
of 83
pro vyhledávání: '"Mushkarov, Oleg"'
Lipschitz constants for the width and diameter functions of a convex body in $\mathbb R^n$ are found in terms of its diameter and thickness (maximum and minimum of both functions). Also, a dual approach to thickness is proposed.
Externí odkaz:
http://arxiv.org/abs/2406.12537
Autor:
Mushkarov, Oleg, Nikolov, Nikolai
We study the relationship between the areas of the consecutive quadrilaterals cut from a convex quadrilateral in the plane by means of a finite or infinite number of straight lines intersecting two of its opposite sides. Moreover, we obtain a geometr
Externí odkaz:
http://arxiv.org/abs/2305.13070
We study the relation between the existence of null conformal Killing vector fields and existence of compatible complex and para-hypercomplex structures on a pseudo-Riemannian manifold with metric of signature (2,2). We establish first the topologica
Externí odkaz:
http://arxiv.org/abs/2204.13770
Autor:
Davidov, Johann, Mushkarov, Oleg
Publikováno v:
Proceedings of the Steklov Institute of Mathematics 311 (2020); in Russian, pp. 84-105, in English, pp. 78-97
In this paper we review some results on the Riemannian and almost Hermitian geometry of twistor spaces of oriented Riemannian $4$-manifolds with emphasis on their curvature properties.
Externí odkaz:
http://arxiv.org/abs/2102.03806
Autor:
Davidov, Johann, Mushkarov, Oleg
Publikováno v:
Ann. Mat. Pure Appl. 197 (2018), 185-209
In this paper we describe the oriented Riemannian four-manifolds $M$ for which the Atiyah-Hitchin-Singer or Eells-Salamon almost complex structure on the twistor space ${\mathcal Z}$ of $M$ determines a harmonic map from ${\mathcal Z}$ into its twist
Externí odkaz:
http://arxiv.org/abs/1611.06496
Autor:
Mushkarov, Oleg, Yankov, Christian L.
We prove that any left-invariant symplectic almost complex structure on a Thurston manifold which is compatible with its canonical left-invariant Riemannian metric has holomorphic type 1.
Comment: 10 pages; accepted for publication in Annales Po
Comment: 10 pages; accepted for publication in Annales Po
Externí odkaz:
http://arxiv.org/abs/1611.03117
We find geometric conditions on a four-dimensional almost Hermitian manifold under which the almost complex structure is a harmonic map or a minimal isometric imbedding of the manifold into its twistor space.
Comment: to appear in J. Geom. Phys
Comment: to appear in J. Geom. Phys
Externí odkaz:
http://arxiv.org/abs/1504.01610
Autor:
Andreescu, Titu, Mushkarov, Oleg
Publikováno v:
The American Mathematical Monthly, 2018 Nov 01. 125(9), 811-819.
Externí odkaz:
https://www.jstor.org/stable/48662288
In this paper we determine the Gray-Hervella classes of the compatible almost complex structures on the twistor spaces of oriented Riemannian four-manifolds considered by G. Deschamps
Externí odkaz:
http://arxiv.org/abs/1307.0446
We study the problem of existence of geometric structures on compact complex surfaces that are related to split quaternions. These structures, called para-hypercomplex, para-hyperhermitian and para-hyperk\"ahler are analogs of the hypercomplex, hyper
Externí odkaz:
http://arxiv.org/abs/1205.2580