Non-invariant complex structures on Lie groups are not biholomorphic to invariant ones.
problem Understanding non-invariant deformations of complex structures on Lie groups.
method Computed cohomologies to show non-biholomorphicity.
result Non-invariant complex structures are not biholomorphic to invariant ones.
The paper explores invariant vs non-invariant complex structures on Lie groups.
problem Understanding complex structures on Lie groups and their properties.
method Analysis of invariant and non-invariant almost complex structures on compact quotients of Lie groups.
result New computations of Kodaira dimension for invariant and non-invariant structures.
Defines invariants for reflection groups and connects them to Frobenius structures.
problem Understanding invariants for reflection groups and their relation to Frobenius structures.
method Defines good basic invariants and shows their connection to Frobenius structures.
result Good basic invariants for reflection groups lead to Frobenius structure constants.
The study characterizes real flag manifolds with invariant generalized almost complex structures.
problem Characterizing real flag manifolds with invariant generalized almost complex structures.
method Characterization through invariant B-transformations and classification of structures. result No GM2-maximal real flag manifolds admit integrable invariant generalized almost complex structures. Global invariant for path structures and differential equations defined on torus.
problem Global invariant for path structures and differential equations.
method Computed as a secondary invariant from a Cartan connection on a canonical bundle.
result Formula for global invariant of second order differential equations on torus.
The paper explores left invariant k-symplectic structures on Lie groups with bi-invariant metrics.
problem Existence and properties of left invariant k-symplectic structures on Lie groups with bi-invariant metrics.
method Analyzing compact semi-simple Lie groups and specific Lie groups with bi-invariant pseudo-Riemannian metrics.
result Compact semi-simple Lie groups and many Lie groups do not carry left invariant k-symplectic structures, except for specific cases.
Paper defines invariants for elliptic Weyl groups and connects them to Frobenius structures.
problem Defining invariants for elliptic Weyl groups.
method Defines a set of good basic invariants and shows their connection to Frobenius structures.
result Good basic invariants give flat invariants and structure constants of Frobenius structures.
Study proves all left-invariant contact structures on 3D Lie groups are tight.
problem Characterizing tightness of left-invariant contact structures on 3D Lie groups.
method Riemannian methods and unique factorization property for Lie groups.
result All left-invariant contact structures on 3D Lie groups are tight.
New invariants for singular knots and links defined using shadow structures.
problem Defining invariants for singular knots and links.
method Introducing action of singquandles on sets and defining shadow counting and polynomial invariants.
result Enhanced shadow counting invariant for singular knots and links.
We collect the recent results on invariant f-structures in the generalized Hermitian geometry. Here the canonical f-structures on homogeneous k-symmetric spaces play a remarkable role. Specifically, these structures provide a wealth of invariant examples for the classes of nearly Kaehler f-structures, Hermitian f-struc…
Paper studies invariant distributions of bi-Hamiltonian structures.
problem Integrability of invariant distributions in bi-Hamiltonian structures.
method Description and investigation of invariant distributions.
result All invariant distributions of non-degenerate bi-Hamiltonian structures are described.
Study structural invariants of Goursat distributions related to curve singularities.
problem Understanding local invariants of Goursat distributions.
method Investigate structural invariants akin to curve singularities on surfaces.
result Relate structural invariants to small growth invariants in the sequel.
Classifies invariant spin structures on spheres.
problem Determining which Lie groups preserve the unique spin structure.
method Two approaches: differential of actions and representation theory.
result Classification of Lie groups preserving the spin structure.
This paper studies moduli spaces of statistical structures on Lie groups.
problem Understanding statistical structures on Lie groups.
method Introduced and studied moduli spaces for left-invariant statistical structures on Lie groups.
result Moduli spaces of left-invariant Riemannian metrics are singletons for certain Lie groups.
Deep analysis of KV-Poisson structures and new invariant computed.
problem Understanding KV-Poisson structures and their properties.
method Classification, properties analysis, and computation of Cohomological groups.
result KV-Poisson structures give rise to a new Cohomological invariant.
Knot invariants from XC-structures on Sweedler algebra are trivially determined.
problem Defining and characterizing knot invariants from XC-structures.
method Examining XC-structures on the Sweedler algebra and their relation to knot invariants.
result Knot invariants from XC-structures on Sweedler algebra are completely determined by the framing of the knot.
Study left invariant spray structures on Lie groups, calculating curvature and geodesics.
problem Understanding curvature and geodesics in left invariant spray structures on Lie groups.
method Use invariant frames and canonical bi-invariant Berwald spray structure to analyze left invariant spray structures.
result Established correspondence between geodesics and inverse integral curves of spray vector fields.
Researchers compute the ν-invariant for specific G2-structures on nilmanifolds.
problem Detecting connected components of G2-structure moduli spaces.
method Defined and computed the ν-invariant using Mathai-Quillen currents, harmonic spinors, and η-invariants.
result Determined the parity of harmonic spinor dimensions and deduced ν vanishing on invariant spinors.
Classifies and computes cohomologies of complex structures on Lie groups.
problem Classifying and computing cohomologies of complex structures on Lie groups.
method Complete classification and computation of invariant cohomologies for left invariant structures.
result Computed invariant cohomologies for various generalized complex and Kähler structures.
Study invariant Poisson structures on homogeneous manifolds, algebraically and geometrically.
problem Characterize and understand invariant Poisson structures on homogeneous manifolds.
method Algebraic characterization and bijective correspondence with Lie subalgebras, symplectic foliation, and invariant contravariant connections.
result Established a connection between invariant Poisson tensors and Lie subalgebras with a 2-cocycle.
The paper defines and explores Poisson-Nijenhuis structures on Lie groupoids.
problem Defining and understanding Poisson-Nijenhuis structures on Lie groupoids.
method Introducing and studying right-invariant Poisson-Nijenhuis structures on Lie groupoids and their infinitesimal counterparts.
result A mutual correspondence between (Λ,n)−structures on Lie algebroids and Poisson-Nijenhuis structures on Lie groupoids. Researchers compute the ν-invariant for specific G2-structures on Aloff-Wallach spaces.
problem Computing the ν-invariant for G2-structures on Aloff-Wallach spaces.
method Using Goette's formulas for η-invariants of homogeneous spaces, derived an explicit expression for ν.
result For the nearly-parallel G2-structures φ± on Nk,l, the ν-invariant is ν(φ±) = ±41.
The paper classifies invariant structures on complex almost Abelian groups.
problem Investigating invariant geometric structures on almost Abelian Lie groups.
method Explicit formulas for Haar measures, modular function, and generator fields were derived.
result All invariant tensor fields have constant coefficients in the invariant frame.
Survey of LMO invariant for 3-manifolds using Kirby structures.
problem Developing a combinatorial approach to the LMO invariant of 3-manifolds.
method Introducing Kirby structures and pre-LMO structures to yield multiplicative invariants.
result Construction and equivalence of two families of invariants, leading to the LMO invariant.
The study of invariant SKT structures on nilmanifolds, focusing on 2-step cases.
problem Existence of invariant SKT structures on complex nilmanifolds.
method Construction of examples and negative answer to the existence of invariant SKT structures on higher-step nilmanifolds.
result Negative result on the existence of invariant SKT structures on k-step (k>2) complex nilmanifolds. Researchers compute mod 2 Seiberg-Witten invariants for spin structures and families.
problem Computing mod 2 Seiberg-Witten invariants for spin structures and families.
method Using Pin(2)-symmetry and localisation in equivariant cohomology, the researchers enhance and compute the invariants.
result The mod 2 Seiberg-Witten invariants are computed for spin structures and families, confirming the simple type conjecture mod 2.
We prove that any invariant strong Kahler structure with torsion (SKT structure) on a flag manifold M=G/K of a semisimple compact Lie group G is Kahler. As an application we describe invariant generalized Kahler structures on M.
We classify invariant almost complex structures on homogeneous manifolds of dimension 6 with semi-simple isotropy. Those with non-degenerate Nijenhuis tensor have the automorphism group of dimension either 14 or 9. An invariant almost complex structure with semi-simple isotropy is necessarily either of specified 6 homo…
In this work we study the existence of invariant almost complex structures on real flag manifolds associated to split real forms of complex simple Lie algebras. We show that, contrary to the complex case where the invariant almost complex structures are well known, some real flag manifolds do not admit such structures.…
New method classifies symplectic structures on Lie groups.
problem Classifying left-invariant symplectic structures on Lie groups.
method Using moduli space of left-invariant nondegenerate 2-forms.
result Classified left-invariant symplectic structures on specific Lie groups.
This paper connects complex hyperkähler structures to Donaldson-Thomas invariants.
problem Describing geometric structures on spaces of stability conditions.
method Introducing Joyce structures and showing their relation to complex hyperkähler structures.
result A Joyce structure on a complex manifold defines a complex hyperkähler structure on its tangent bundle.
This research classifies invariant complex structures and Kähler metrics on principal bundles.
problem Classifying invariant complex structures and Kähler metrics on principal bundles.
method Using Wang's theory of invariant connections and the Levi-Civita connection, the study provides direct geometric proofs and extends the classification from Hermitian to general symmetric spaces.
result The invariant integrable complex structures are unique in the reduced frame bundles of the upper half-plane and complex projective spaces.
The paper explores how to make machine learning models robust to domain shifts.
problem Machine learning models are unreliable in domains different from training.
method Introducing a broad formal notion of invariance and causal structures.
result The true underlying causal structure of the data plays a critical role in robustness.
Local tri-Hamiltonian structure for Ablowitz-Ladik hierarchy established.
problem Establishing a tri-Hamiltonian structure for the Ablowitz-Ladik hierarchy.
method Constructing a local tri-Hamiltonian structure and computing central invariants.
result Central invariants of one bi-Hamiltonian structure are 1/24, and dispersionless limit matches Frobenius manifold.
Classifies left invariant Kundt structures on 3D Lie groups.
problem Understanding Kundt spacetimes and their properties.
method Analyzes local structure and properties of left invariant Kundt structures.
result Classifies all left invariant Kundt structures on 3D simply connected unimodular Lie groups.
We study the secondary structure of RNA determined by Watson-Crick pairing without pseudo-knots using Milnor invariants of links. We focus on the first non-trivial invariant, which we call the Heisenberg invariant. The Heisenberg invariant, which is an integer, can be interpreted in terms of the Heisenberg group as wel…
Invariant description of SU(2)-structures on 5-manifolds developed.
problem Characterizing and describing SU(2)-structures on spin 5-manifolds.
method Spinor approach to characterize subspaces inducing SU(2) isomorphism, quaternionic structure induction, and invariant derivation of covariant derivatives.
result Invariance of certain components of the covariant derivative ablaφ derived. New algebraic structure helps distinguish braids.
problem Distinguishing braids using mathematical invariants.
method Defined pointed racks and used them to create braiding invariants.
result New invariants can distinguish braids not previously possible.
Study invariant spin^r structures on homogeneous spaces.
problem Classify invariant spin^r structures on homogeneous spaces.
method Introduce and study G-invariance of spin^r structures on homogeneous spaces. result Classification of invariant spin^r structures in terms of isotropy representation.
ISL improves causal structure learning with invariant structures across different environments.
problem Improving causal structure discovery for better generalization and explainability.
method ISL splits data into environments, learns invariant structures, and selects optimal classifiers based on graph structures.
result ISL accurately discovers causal structures and outperforms alternative methods on synthetic and real-world datasets.
New method extends invariant reduction to rescaled geometric structures.
problem Computing invariant geometric structures under symmetries.
method Extends invariant reduction to rescaled structures using shift rule.
result Emergence and loss of invariance in reductions.
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.
A strong KT (SKT) manifold consists of a Hermitian structure whose torsion three-form is closed. We classify the invariant SKT structures on four-dimensional solvable Lie groups. The classification includes solutions on groups that do not admit compact four-dimensional quotients. It also shows that there are solvable g…
Generalizes Dolbeault cohomology computation to Levi-flat CR structures on compact Lie groups.
problem Computing Dolbeault cohomology for Levi-flat CR structures on compact Lie groups.
method Algebraic classification of left-invariant CR structures combined with Pittie's result on compact Lie groups.
result Generalization of Dolbeault cohomology computation to Levi-flat CR structures.
No left-invariant hypercomplex structures found on compact Lie groups.
problem Existence of left-invariant hypercomplex structures on compact Lie groups.
method Elementary algebraic arguments to show non-existence.
result Compact Lie groups of dimension 4n do not admit left-invariant hypercomplex structures. Characterizes invariant contact metric structures on tangent sphere bundles of compact symmetric spaces.
problem Identifying invariant contact metric structures on tangent sphere bundles of compact symmetric spaces.
method Characterization through invariant Riemannian metrics and Killing vector fields.
result A family of invariant contact metric structures is obtained on tangent sphere bundles of compact symmetric spaces with rank greater than or equal to two.
New algebraic structures help categorify link invariants.
problem Classifying and distinguishing links and virtual links.
method Introducing mc-biquandles and categorifying homsets.
result New link invariants defined via mc-biquandle coloring quivers.
Classifies complex Dirac structures with invariants and local structure.
problem Classifying complex Dirac structures.
method Introducing invariants (order, type), proving existence and splitting theorems.
result Pointwise classification and local structure of complex Dirac structures.