arXiv research

Paper calculates curvatures of metrics from isotropic structures.

The paper studies integrability of isotropic almost complex structures and harmonic unit vector fields.

The paper classifies almost isotropic Kähler manifolds, proving their properties.

In the present work we consider an almost complex manifold with Norden metric (i.e. a metric with respect to which the almost complex structure is an antiisometry). On such a manifold we study a linear connection preserving the almost complex structure and the metric and having a totally skew-symmetric torsion tensor. …

We consider an almost complex manifold with Norden metric (i. e. a metric with respect to which the almost complex structure is an anti-isometry). On such a manifold we study a linear connection preserving the almost complex structure and the metric and having a totally skew symmetric torsion tensor (i. e. a 3-form). W…

Almost hypercomplex pseudo-Hermitian manifolds are considered. Isotropic hyper-Kähler manifolds are introduced. A 4-parametric family of 4-dimensional manifolds of this type is constructed on a Lie group. This family is characterized geometrically. The condition a 4-manifold to be isotropic hyper-Kähler is given.

We study two types of isotropic planes: weakly isotropic and strongly isotropic planes. We prove that a Riemannian manifold of indefinite metric is conformally flat if and only if its curvature tensor vanishes on all the strongly isotropic planes. We specialize the plane axiom for Riemannian manifolds of indefinite met…

Study isotropic curves on complex quadric with geometric relations.

To each non-isotropic almost-complex immersion of a 2-torus into $S ^ 6$ we associate an algebraic curve, called the spectral curve, and a linear flow in the intersection of two Prym varieties on this spectral curve. We show that generically the spectral curve is smooth and compute the dimension of the moduli space o…

We study integrability of generalized almost contact structures, and find conditions under which the main associated maximal isotropic vector bundles form Lie bialgebroids. These conditions differentiate the concept of generalized contact structures from a counterpart of generalized complex structures on odd-dimensiona…

The basic class of the non-integrable almost complex manifolds with Norden metric is considered. Its curvature properties are studied. The isotropic Kaehler type of investigated manifolds is introduced and characterized geometrically.

The paper classifies flag manifolds with specific isotropy components and finds conditions for Kähler-like scalar curvature.

In this paper, we study the second approximate Matsumoto metric on a manifold M. We prove that F is of scalar flag curvature and isotropic S-curvature if and only if it is isotropic Berwald metric with almost isotropic flag curvature.

Study closed G2-structures with T3-symmetry, classifying them into types and deriving hypersymplectic structures.

Paper establishes a relation between Berwald scalar curvature and S-curvature.

The isotropic almost complex structures induce a Riemannian metric $g_{δ,σ}$ on TM, which are the generalized type of Sasakian metric. In this paper, the Levi-Civita connection of $g_{δ,σ}$ is calculated and the harmonicity of unit vector fields from $(M, g)$ to $(S(M), i*g_{δ,0})$ is investigated, where $i*g_{δ,0}$ is…

We show that the finiteness length of an $S$-arithmetic subgroup $Γ$ in a noncommutative isotropic absolutely almost simple group $G$ over a global function field is one less than the sum of the local ranks of $G$ taken over the places in $S$. This determines the finiteness properties for arithmetic subgroups in isotro…

Study of homogeneous spacetimes with isotropic symmetry and their symmetries.

In the Friedmann Model of the universe, cosmologists assume that spacelike slices of the universe are Riemannian manifolds of constant sectional curvature. This assumption is justified via Schur's Theorem by stating that the spacelike universe is locally isotropic. Here we define a Riemannian manifold as almost locally…

In this paper, we define some non-Riemannian curvature properties for Cartan spaces. We consider Cartan space with the m-th root metric. We prove that every m-th root Cartan space of isotropic Landsberg curvature, or isotropic mean Landsberg curvature, or isotropic mean Berwald curvature reduces to a Landsberg, weakly …

Constructs a Morse-Bott function on symplectic Grassmannians.

We prove a conjecture of Gromov's to the effect that manifolds with isotropic curvature bounded below by 1 (after possibly rescaling) are macroscopically 1-dimensional on the scales greater than 1. As a consequence we prove that compact manifolds with positive isotropic curvature have virtually free fundamental groups.…

The paper explores almost Ricci solitons on Finsler spaces, proving conditions for their existence.

We prove that Ricci flows with almost maximal extinction time must be nearly round, provided that they have positive isotropic curvature when crossed with $\mathbb{R}^{2}$. As an application, we show that positively curved metrics on $S^{3}$ and $RP^{3}$ with almost maximal width must be nearly round.

Study stabilizers of isotropic classes in rational 4-manifolds, finding diffeomorphisms that almost preserve Lefschetz fibrations.

Study on special Finsler metrics with conditions for Riemannian and isotropic properties.

Harmonic almost complex structures on specific Lie groups and solvmanifolds identified.

Study shows almost complex structures with certain tensor properties are prevalent.

Almost hypercomplex manifolds with Hermitian and Norden metrics and more specially the corresponding quaternionic Kaehler manifolds are considered. Some necessary and sufficient conditions the investigated manifolds be isotropic hyper-Kaehlerian and flat are found. It is proved that the quaternionic Kaehler manifolds w…

If Gamma is a nonuniform, irreducible lattice in a semisimple Lie group whose real rank is greater than 1, we show Gamma contains a subgroup that is isomorphic to a nonuniform, irreducible lattice in either SL(3,R), SL(3,C), or a direct product SL(2,R)^m x SL(2,C)^n$, with m + n > 1. (In geometric terms, this can be in…

Study on invariant almost complex structures on real flag manifolds.

The paper classifies pseudo-isotropic and lightlike pseudo-isotropic Lagrangian surfaces.

New isotropic tori found in complex space, not Hamiltonian isotopic.

Study on biharmonic almost complex structures on compact manifolds.

Let $(M^n,g)$, $n \ge 4$, be a compact simply-connected Riemannian manifold with nonnegative isotropic curvature. Given $0<l\le L$, we prove that there exists $\eps = \eps (l,L,n)$ satisfying the following: If the scalar curvature $s$ of $g$ satisfies $l \le s \le L$ and the Einstein tensor satisfies $$ | Ric - \fr…

The paper proves conditions for almost complex manifolds to admit almost complex structures through connected sums.

The paper studies lifts of complex structures on a manifold.

Study on Kodaira dimension of SU(m)-structures on almost complex manifolds.

Odd m-fold connected sums of complex projective spaces admit almost complex structures.

The study characterizes real flag manifolds with invariant generalized almost complex structures.

Almost complex structures found on many homotopy complex projective spaces.

The $B$-connection on almost complex manifolds with Norden metric is an analogue of the first canonical connection of Lihnerovich in Hermitian geometry. In the present paper it is considered a $B$-connection in the class of the quasi-Kähler manifold with Norden metric. Some necessary and sufficient conditions are deriv…

Study transverse Dolbeault cohomology for almost complex structures.

The paper proves smoothness of weakly biharmonic almost complex structures in dimension four.

Solves Monge-Ampère on non-integrable manifolds.

The paper studies almost complex structures on ACH Einstein manifolds and finds deformation results.

Study on Kodaira dimension of specific solvmanifolds without complex structures.

Survey on harmonic almost complex structures on Riemannian manifolds.