Study geodesic orbit property on pseudo-Riemannian H-type nilmanifolds.
problem Characterize geodesic orbit property for pseudo-Riemannian H-type Lie groups.
method Extend results from Riemannian to pseudo-Riemannian H-type Lie groups, focusing on minimal admissible Clifford modules.
result Complete characterization of geodesic orbit property for pseudo-Riemannian H-type Lie groups.
New Lie groups generalize H-type groups with nondegenerate centers.
problem Generalizing H-type groups with nondegenerate centers.
method Defined and investigated 2-step nilpotent Lie groups.
result Geometric properties of new Lie groups investigated.
Defines new structures on Courant algebroids, focusing on B_n types.
problem Exploring new geometric structures on Courant algebroids.
method Introducing B_n-generalized pseudo-Hermitian and pseudo-Kahler structures on odd exact Courant algebroids.
result Explicit descriptions of these structures on specific types of Courant algebroids.
Following previous work of the second author, we establish more properties of groups of circle homeomorphisms which admit invariant laminations. In this paper, we focus on a certain type of such groups-so-called pseudo-fibered groups, and show that many 3-manifold groups are examples of pseudo-fibered groups. We then p…
Termination proof for Cartan's method in constant type problems.
problem Proving termination of Cartan's equivalence method for constant type problems.
method Groupoid approach to Lie pseudo-groups and Cartan-Kuranishi theorem.
result Cartan's method terminates at involution or complete reduction for constant type problems.
It is known that all left-invariant pseudo-Riemannian metrics on H3 are algebraic Ricci solitons. We consider generalizations of Riemannian H-type, namely pseudoH-type and pH-type. We study algebraic Ricci solitons of left-invariant Lorentzian metrics on 2-step nilpotent Lie groups of both types.
This work deals with the structure of the isometry group of pseudo-Riemannian 2-step nilmanifolds. We study the action by isometries of several groups and we construct examples showing substantial differences with the Riemannain situation; for instance the action of the nilradical of the isometry group does not need to…
The study shows pseudo-Anosovs are common in mapping class groups.
problem Counting pseudo-Anosovs in mapping class groups.
method Using weakly contracting isometries and Morse elements.
result Pseudo-Anosovs are generic in mapping class groups.
We study conformal actions of connected nilpotent Lie groups on compact pseudo-Riemannian manifolds. We prove that if a type-(p,q) compact manifold M supports a conformal action of a connected nilpotent group H, then the degree of nilpotence of H is at most 2p+1, assuming p <= q; further, if this maximal degree is atta…
Study on pseudo-Riemannian metrics on Lie groups, finding new non-Einstein examples.
problem Characterizing and finding non-Einstein pseudo-Riemannian metrics on Lie groups.
method Analyzing left invariant metrics, using double extension process, and constructing examples.
result Construction of infinitely many new explicit examples of non-Einstein pseudo-Riemannian metrics on Lie groups.
The aim of our paper is to construct pseudo H-type algebras from the covering free nilpotent two-step Lie algebra as the quotient algebra by an ideal. We propose an explicit algorithm of construction of such an ideal by making use of a non-degenerate scalar product. Moreover, as a bypass result, we recover the existe…
Study fundamental solutions for a class of ultra-hyperbolic operators on pseudo H-type groups.
problem Investigating fundamental solutions for a specific class of ultra-hyperbolic operators on pseudo H-type groups. method Analyzing the algebraic structure of pseudo H-type Lie groups and their associated operators, using families of fundamental solutions and properties of classical special functions. result Found fundamental solutions for the operator in the case r=0, s>0 and proved that no fundamental solution exists in the space of tempered distributions for the case r>0. Study pseudo-Riemannian Sasaki metrics on solvable Lie groups.
problem Characterize and classify pseudo-Riemannian Sasaki solvmanifolds.
method Sasaki reduction and pseudo-Kähler quotient under Reeb vector field action.
result Classify pseudo-Riemannian Sasaki solvmanifolds in dimensions 5 and 7.
We construct the first known examples of compact pseudo-Riemannian manifolds having an essential group of conformal transformations, and which are not conformally flat. Our examples cover all types (p,q), with 2≤p≤q.
The paper constructs Einstein Sasaki metrics on solvable Lie groups.
problem Constructing left-invariant Einstein pseudo-Riemannian Sasaki metrics on solvable Lie groups.
method Characterizing pseudo-Kähler structures and derivations giving rise to Sasaki-Einstein metrics.
result Classification of z-standard Sasaki solvable Lie algebras of dimension ≤7. 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.
In the present paper we study the rigidity of 2-step Carnot groups, or equivalently, of graded 2-step nilpotent Lie algebras. We prove the alternative that depending on bi-dimensions of the algebra, the Lie algebra structure makes it either always of infinite type or generically rigid, and we specify the bi-dimensions …
Study classifies metrics on anti-de Sitter spacetime with specific symmetries.
problem Classifying metrics with specific symmetries on anti-de Sitter spacetime.
method Used classification techniques for pseudo-Riemannian and almost contact metric structures.
result Obtained classifications of homogeneous structures on anti-de Sitter spacetime.
New examples of surface bundles found over surfaces.
problem Finding compact atoroidal surface bundles.
method Type-preserving homomorphism from knot complement to mapping class group.
result Infinitely many commensurability classes of surface subgroups.
The paper finds pseudo-Anosov-like maps on an infinite ladder surface.
problem Exploring dynamics on infinite surfaces.
method Lifts Penner-type pseudo-Anosov maps from a closed surface to an infinite ladder surface.
result Existence and properties of pseudo-Anosov-like maps on the infinite ladder surface.
In this paper, we propose a weak version of quotient for the algebraic action of a group on a variety, which we shall call a pseudo-quotient. They arise when we focus on the purely topological properties of good GIT quotients regardless of their algebraic properties. The flexibility granted by their topological nature …
The Cartan's method of equivalence and moving coframe method has been applied to solve the local equivalence problem for KDV-type equations under the action of a pseudo-group of contact transformations. The structure equations, the sets of differential invariants for symmetry groups and equivalent conditions of these e…
The symplectic representation of mapping classes is not surjective for certain types of mapping classes.
problem The surjectivity of the symplectic representation of mapping classes, particularly pseudo-Anosov ones, is not always preserved.
method Explicit construction of symplectic matrices with a bi-Perron leading eigenvalue that cannot be represented by orientable pseudo-Anosov mapping classes.
result The symplectic representation of orientable pseudo-Anosov mapping classes is not surjective.
Complete description of flat Lorentzian Lie groups solved.
problem Long-standing open problem in pseudo-Riemannian Lie groups.
method Refined analysis of double extension process and explicit classification of Lie algebras.
result All flat Lorentzian Lie algebras arise from flat Euclidean ones.
Analyzes spinor groups in specific dimensions.
problem Understanding spinor groups in low dimensions.
method Examined Spin(p,q) groups for specific (p,q) values.
result Determined orbit structures of Spin(p,q) groups.
Classifies theories with eight supercharges using pseudo-periodic maps and Riemann surfaces.
problem Classifying theories with eight supercharges using mathematical tools.
method Assumes theories are given by genus g fibrations of Riemann surfaces, uses pseudo-periodic maps of negative type in mapping class group.
result Identifies dual graphs and 3d mirror quivers, unifies various SCFTs in combinatorial framework.
In this work, we study the pseudo-Riemannian submanifolds of a pseudo-sphere with 1-type pseudo-spherical Gauss map. First, we classify the Lorentzian surfaces in a 4-dimensional pseudo-sphere Ss4(1) with index s, s=1,2, and having harmonic pseudo-spherical Gauss map. Then we give a characterization the…
Unified treatment of two extension problems using heat equation in Heisenberg group.
problem Two extension problems for pseudo-differential operators in Heisenberg group.
method Heat equation, fractional powers, semigroup methods.
result Explicit computation of fundamental solutions for pseudo-differential operators.
In Garside groups, axes of Morse elements are strongly contracting.
problem Understanding the dynamics of Morse elements in Garside groups.
method Analyzing the Cayley graph of Garside groups modulo their center, using Garside generators.
result Morse elements act loxodromically on the additional length graph of Garside groups.
Paper constructs a HOMFLYPT-type invariant for pseudo links.
problem Inability to construct polynomial invariants for pseudo links using Hecke algebra techniques.
method Using a resolution homomorphism and pseudo Hecke algebra of type \(A\), the paper constructs a HOMFLYPT-type invariant for oriented pseudo links.
result The constructed invariant satisfies a natural pseudo skein relation and admits a state-sum formulation.
The paper studies prolongations of Lie algebras associated with pseudo H-type Lie algebras.
problem Investigating prolongations of Lie algebras associated with pseudo H-type Lie algebras. method Analyzing prolongations of associated fundamental graded Lie algebra and associated conformal pseudo-subriemannian fundamental graded Lie algebra.
result The prolongation of the associated conformal pseudo-subriemannian fundamental graded Lie algebra coincides with that of the associated fundamental graded Lie algebra under certain conditions.
Introduces pseudo-codecomposition of transformation groups.
problem Understanding and categorizing transformation groups.
method Introduces pseudo-codecomposition and analyzes properties of transformation groups.
result The class of pseudo-codecomposable transformation groups is a proper intermediate class.
Local and global rigidity results for Lie group actions on pseudo-Riemannian manifolds.
problem Rigidity of isometric actions of simple Lie groups on pseudo-Riemannian manifolds.
method Analyzing normal bundles and using Lie group properties.
result Local and global rigidity theorems for specific Lie groups and manifolds.
Invariant tensors found for specific geometric structures.
problem Finding invariant tensors in specific geometric structures.
method Torsion-free connection and invariant tensors found under twin interchange of metrics and connections.
result Invariant tensors found explicitly in a 4D example.
Minimal surfaces linked to Higgs bundles in pseudo-hyperbolic spaces.
problem Proving Labourie's theorem and extending it to new cases.
method Establishing infinitesimal rigidity of minimal surfaces and using it to prove the theorem.
result New proof of Labourie's theorem and extension to Collier's components.
The paper establishes Schwarz type lemmas for pseudo-Hermitian manifolds.
problem Understanding the geometry and mappings of pseudo-Hermitian manifolds.
method Using sub-Laplacian or Hessian type Bochner formulas and comparison theorems.
result Established Schwarz type results for \emph{CR} maps and transversally holomorphic maps.
New structure found on Lie group tangent bundle.
problem Finding new structures on Lie group tangent bundles.
method Analyzing left invariant structures on Lie groups.
result Tangent bundle of Lie group admits a left-invariant nearly pseudo-Kähler structure.
Let X be a compact connected Kähler manifold equipped with an anti-holomorphic involution which is compatible with the Kähler structure. Let G be a connected complex reductive affine algebraic group equipped with a real form σG. We define pseudo-real principal G--bundles on X; these are generalizations of re…
It is well known that the curvature tensor of a pseudo-Riemannian manifold can be decomposed with respect to the pseudo-orthogonal group into the sum of the Weyl conformal curvature tensor, the traceless part of the Ricci tensor and of the scalar curvature. A similar decomposition with respect to the pseudo-unitary gro…
Study on rank-one ECS manifolds, focusing on dilational type.
problem Characterizing ECS manifolds with specific properties.
method Analyzing properties of pseudo-Riemannian manifolds with parallel Weyl tensor.
result Generic compact rank-one ECS manifolds are either translational or locally homogeneous.
Semisimple Lie groups act transitively on pseudo-Riemannian manifolds, making them flat.
problem Understanding actions of semisimple Lie groups on pseudo-Riemannian manifolds.
method Analyzing the pseudo-Riemannian Lichnerowicz conjecture in homogeneous settings.
result Compact pseudo-Riemannian manifolds on which a semisimple group acts conformally, essentially and transitively, are conformally flat.
Gradient estimates derived for a specific equation on pseudo-Hermitian manifolds.
problem Deriving gradient estimates for solutions of a specific equation on pseudo-Hermitian manifolds.
method Derives gradient estimates for positive solutions of the equation Δbu+aup+1=0 on pseudo-Hermitian manifolds. result Gradient estimates obtained for the positive solutions of the equation.
Compact Lie groups have compact isometry groups with pseudo-Riemannian metrics.
problem Characterizing isometry groups of compact Lie groups with pseudo-Riemannian metrics.
method Analyzing left-invariant pseudo-Riemannian metrics on compact Lie groups.
result Isometry groups of compact Lie groups are compact.
Study on well-posedness of EPDiff equations with pseudo-differential inertia.
problem Analyzing the EPDiff equations with fractional Sobolev metrics.
method Fractional order Sobolev-type metrics on diffeomorphism groups, proving well-posedness.
result Proves local and global well-posedness for EPDiff equations.
Notes on flat pseudo-Riemannian manifolds, focusing on their characterization and properties.
problem Characterizing flat pseudo-Riemannian manifolds and their properties.
method Survey of basic concepts in affine and Riemannian geometry, characterization of flat manifolds, and analysis of Lie groups.
result Characterization and properties of flat pseudo-Riemannian Lie groups and their metrics.
We introduce the notion of a conformal pseudo-subriemannian fundamental graded Lie algebra of semisimple type. Moreover we give a classification of conformal pseudo-subriemannian fundamental graded Lie algebras of semisimple type and their prolongations.
Extends pseudo-differential operators theory to compact Lie groups.
problem Global pseudo-differential operators on compact Lie groups.
method Develops a subelliptic pseudo-differential calculus for compact Lie groups.
result Establishes subelliptic versions of Fefferman and Calderón-Vaillancourt theorems.
The motivation for this paper is to justify a remark of Thurston that the algebraic degree of stretch factors of pseudo-Anosov maps on a surface S can be as high as the dimension of the Teichmüller space of S. In addition to proving this, we completely determine the set of possible algebraic degrees of pseudo-Anoso…