The study extends Kazhdan's theorem to infinite Galois covers of Riemann surfaces.
problem Proving uniform convergence of canonical forms on towers of Riemann surfaces.
method Generalizing Kazhdan's theorem to infinite Galois covers, proving a Gauss--Bonnet type theorem.
result Uniform convergence of canonical forms on towers of Riemann surfaces under infinite Galois covers.
Extends Gromov's theorem with amenable covers.
problem Gromov's Vanishing Theorem limitations.
method Gromov's multicomplex theory, relative bounded cohomology.
result Relative version of Gromov's Vanishing Theorem.
Paper extends theorem on covering spaces and Jordan curves.
problem Covering and extending theorems for Alexandrov spaces.
method Introduces proximal homotopic cycles to extend the Mitsuishi-Yamaguchi theorem.
result Extensions of the Mitsuishi-Yamaguchi Good Covering Theorem and Jordan curve theorem.
Generalizes Leighton's theorem to cube complexes.
problem Extending graph covering theorem to cube complexes.
method Generalizes Leighton's theorem to a family of cube complexes.
result Cube complexes have common finite covers.
New proof of graph covering theorem for graphs with fins.
problem Graph covering theorem for graphs with fins.
method New proof using Haar measure.
result Pattern rigidity for free groups with line patterns.
Local mixing theorem for abelian covers of hyperbolic 3-manifolds.
problem Mixing properties of frame flows on abelian covers.
method Local mixing theorem for horospherical subgroups on abelian covers.
result Classification of invariant measures for horospherical subgroups.
Note proves index theorem for non-elliptic Heisenberg operators.
problem Proving index theorem for non-elliptic Heisenberg operators.
method Galois covering, Heisenberg elliptic differential operators, Γ-index theorem. result Example of Heisenberg operators with non-trivial Γ-index. Extends canonical measures to metric graphs and proves a generalized Kazhdan's theorem.
problem Understanding limiting measures on metric graphs and their relation to hyperbolic measures.
method Introducing hyperbolic measures on universal covers of metric graphs and proving a generalized Kazhdan's theorem.
result All limiting measures on metric graphs satisfy a Gauss-Bonnet formula, interpreted as a trace formula.
The paper proves a theorem about torsion and Morse functions for covering spaces.
problem Proving a theorem about torsion and Morse functions for covering spaces.
method Using a fiberwise Morse function and the Novikov-Shubin invariant.
result Proves the Cheeger-Müller theorem for L2-analytic torsion form. Study shows a central limit theorem for random coverings of manifolds with nilpotent groups.
problem Understanding the distribution of connected components in random coverings of manifolds with nilpotent fundamental groups.
method Used sampling homomorphisms from the fundamental group into the symmetric group and subgroup growth zeta functions of nilpotent groups.
result Proved a central limit theorem for the number of connected components of these random coverings.
It was pointed out to us that the proof of a crucial lemma (Lemma 5.3) in the paper is incorrect. Thus the approximation theorem (Theorem 0.1) for L^2 torsion of an amenable covering of a finite simplicial complex remains unproved. However, results and proofs of the first four sections (in particular, the approximation…
This paper extends the Good Covering Theorem and Jordan Curve Theorem for proximal Alexandrov spaces.
problem Extending the Good Covering Theorem and Jordan Curve Theorem to proximal Alexandrov spaces.
method Introducing path cycles and using them to extend the Good Covering Theorem and Jordan Curve Theorem.
result Extensions of the Mitsuishi-Yamaguchi Good Covering Theorem and Jordan Curve Theorem for proximal Alexandrov spaces.
Support theorem proved for X-ray transform on certain non-compact manifolds.
problem Support theorem for X-ray transform on non-compact manifolds with conjugate points.
method Use of plane covers and support theorem for simple manifolds by Krishnan.
result Support theorem proved for simply connected 2-step nilpotent Lie groups and some non-homogeneous 3D manifolds.
Study properties of balanced hyperbolic compact complex manifolds.
problem Understanding cohomology and harmonic spaces of balanced hyperbolic manifolds.
method Proved vanishing theorems and Hard Lefschetz-type theorems for balanced hyperbolic compact complex manifolds.
result Non-existence of certain L1 currents on the universal covering space of a balanced hyperbolic manifold. The study finds a limit on subgroup complexity in hyperbolic 3-manifold groups.
problem Understanding subgroups of bounded rank in hyperbolic 3-manifold groups.
method Proving a finiteness theorem for subgroups of bounded rank.
result Every bounded rank covering tower of closed hyperbolic 3-manifolds is a tower of finite covers associated to a fibration over a 1-orbifold.
The study extends convergence theorems for Ricci-limit spaces with bounded curvature.
problem Understanding convergence properties of Ricci-limit spaces with bounded curvature.
method Establishing C1,α-regularities and applying Fukaya's fibration theorem. result Optimal generalization of Fukaya's fibration theorem to C1,α limit spaces. Simplified proof of a theorem about 3D shapes.
problem Proving a theorem about foliations on 3-manifolds.
method Using foliated branched covers.
result A simple proof of Novikov's theorem.
The abstract proves a global splitting theorem for Poisson manifolds.
problem Decomposing compact Kähler Poisson manifolds into simpler components.
method Proving a global splitting theorem using symplectic leaves and finite étale covers.
result Compact Kähler Poisson manifolds can be split into simpler components.
The paper describes relations between Liouville type theorems for solutions of a periodic elliptic equation (or a system) on an abelian cover of a compact Riemannian manifold and the structure of the dispersion relation for this equation at the edges of the spectrum. Here one says that the Liouville theorem holds if th…
The paper extends a theorem to manifolds with local Ricci bounded covering geometry.
problem Understanding collapsed manifolds with specific Ricci curvature properties.
method Extending a theorem from nilpotent fiber bundles to manifolds with local (ρ,v)-bound Ricci covering geometry. result Manifolds with local (ρ,v)-bound Ricci covering geometry are diffeomorphic to infra-nilmanifolds. Cover's theorem extended to stochastic portfolio theory, showing yield equivalence.
problem Model-free yield comparison in stochastic portfolio theory.
method Extending Cover's theorem to variable rebalancing rules and comparing with numeraire portfolio.
result Optimal long run yield is equivalent across three approaches.
Generalizes tools for studying collapsed manifolds to new geometry.
problem Studying collapsed manifolds with bounded sectional curvature.
method Generalizes fibration and stability theorems for compact group actions on manifolds with local bounded Ricci covering geometry.
result Two generalized results used in Xiaochun Rong's work on almost flat manifolds.
This note explores comparison geometry concepts and theorems.
problem Exploring various comparison theorems in geometry.
method Analyzes Rauch and Toponogov theorems and their applications.
result Introduction of Gromov-Hausdorff convergence and Alexandrov Spaces.
New proofs show how to embed certain 3D shapes into a 4D ball.
problem Embedding specific 3D shapes into a 4D ball.
method Embedded surfaces in the 4-ball and branched double covers.
result New proofs of embedding theorems for rational homology balls.
New proofs and refined theorems on bounded cohomology.
problem Properties of bounded cohomology and comparison map.
method Homotopy-theoretic properties and generalizations.
result New proofs and refined versions of vanishing and covering theorems.
Extends Borsuk-Ulam theorem with applications in sphere coverings and colorings.
problem Complexity bounds and structural insights for triangulated sphere mappings.
method Combinatorial labeling and order type analysis of finite point sets.
result New topological Hall theorem and generalizations of hypergraph Hall theorems.
Study smooth linear statistics on random covers of hyperbolic surfaces, showing central limit and variance results.
problem Analyzing fluctuations and energy variance of random covers of compact hyperbolic surfaces.
method Examining fluctuations in a small energy window around a fixed energy level, considering the variance of a typical surface, using a double limit where n and L go to infinity. result Distribution of fluctuations tends to a Gaussian with variance of GOE/GUE, and energy variance of a typical random n-cover is that of GOE/GUE. Lectures on symplectic and Poisson geometry, quantization, and quantum field theory.
problem Exploring symplectic and Poisson structures and their applications in quantum field theory.
method Introduction to differential geometry, symplectic geometry, Poisson geometry, and deformation quantization.
result Detailed understanding of symplectic and Poisson structures and their quantization.
The paper finds a criterion for splitting 4-manifolds into 3-manifolds.
problem Finding a geometric-topological decomposition of 4-manifolds.
method Algebraic-topological splitting criterion involving orientation classes and universal covers.
result An equivariant generalization of the Lickorish--Wallace theorem.
Proves an index theorem for foliations using spectral triples.
problem Proving an Atiyah L2 covering index theorem for foliations. method Symbol calculus for foliations and spectral triples.
result Induces the same map on K-theory for two types of spectral triples.
We show that a regular cover of a general topological space provides structure similar to a triangulation. In this general setting we define analogues of simplicial maps and prove their existence and uniqueness up to homotopy. As an application we give simple proofs of sharpened versions of nerve theorems of K. Borsuk …
New examples show causality conditions don't always pass to coverings.
problem Causality conditions not always transfer to coverings.
method Provided explicit examples of spacetimes.
result Causality conditions like causal continuity and simplicity do not always pass to coverings.
The paper proves properties of non-collapsed RCD spaces with bounded covering geometry.
problem Characterizing properties of non-collapsed RCD spaces.
method Analyzing local covering geometry and applying Gromov's almost flat manifold theorem.
result RCD spaces with bounded covering geometry are biHölder homeomorphic to infranil-manifolds.
The classical Lusternik-Schnirelman-Borsuk theorem states that if a d-sphere is covered by d+1 closed sets, then at least one of the sets must contain a pair of antipodal points. In this paper, we prove a combinatorial version of this theorem for hypercubes. It is not hard to show that for any cover of the facets of a …
For large genus, precise monodromy groups are calculated for surface covers.
problem Calculating precise monodromy groups for large genus surface covers.
method Hodge-theoretic methods, including a generic Torelli theorem with coefficients.
result Precise connected monodromy groups are calculated for large genus surface covers.
We show that the Gromov-Hausdorff limit of a sequence of leaves in a compact foliation is a covering space of the limiting leaf which is no larger than this leaf's holonomy cover. We also show that convergence to such a limit is smooth instead of merely Gromov-Hausdorff. Corollaries include Reeb's local stability theor…
We show that simple coverings of B^4 branched over ribbon surfaces up to certain local ribbon moves bijectively represent orientable 4-dimensional 2-handlebodies up to handle sliding and addition/deletion of cancelling handles. As a consequence, we obtain an equivalence theorem for simple coverings of S^3 branched over…
The paper explores conic-line arrangements via Poncelet's theorem and finds families of reducible curves.
problem Understanding the topology of conic-line arrangements using Poncelet's theorem.
method Study unramified double covers induced by Poncelet transverses.
result Existence of families of Zariski pairs of degree 2m+6 for m≥2. The study bounds growth of Hodge numbers and computes L2-Betti numbers for irregular varieties.
problem Bounding growth of normalized Hodge numbers and computing L2-Betti numbers for irregular varieties. method Analysis of abelian covers, weak generic Nakano vanishing theorem, and convergence of plurigenera.
result Optimal bounds on the growth of normalized Hodge numbers and computation of L2-Betti numbers. Paper derives Riccati equation for static spaces and proves its applications.
problem Deriving Riccati equation for static spaces.
method Proving splitting theorem and connectivity of conformal boundary.
result Establishes compactness of universal covering for static triples.
Manifolds covered by two balls are homeomorphic to spheres.
problem Conditions for a manifold to be homeomorphic to a sphere using metric balls.
method Optimal geometric conditions for a Riemannian manifold covered by two metric balls.
result A Riemannian manifold covered by two metric balls is homeomorphic to a sphere.
The Dirichlet random walk on manifolds has a positive escape rate if the cover is non-amenable.
problem Analyzing the stochastic behavior of Dirichlet random walks on manifolds.
method Defining a recursive process on Galoisian covers and proving a theorem about the escape rate.
result The escape rate is positive if and only if the cover is non-amenable.
Isometric embeddings of Teichmüller spaces are derived from branched coverings.
problem Characterizing isometric embeddings of Teichmüller spaces.
method Holomorphic isometric embeddings induced by branched coverings.
result All isometric embeddings of Teichmüller spaces of dimension at least 2 arise from branched coverings.
A canonical branched covering over each sufficiently good simplicial complex is constructed. Its structure depends on the combinatorial type of the complex. In this way, each closed orientable 3-manifold arises as a branched covering over the 3-sphere from some triangulation of S^3. This result is related to a theorem …
Study the topology of Ricci limit spaces using Gromov-Hausdorff limits.
problem Topology of Ricci limit spaces.
method Gromov-Hausdorff limits, slice theorem for isometric pseudo-group actions, uniform diameter bounds.
result Established semi-locally simply connected property and described universal cover.
Researchers lift spectral ζ-invariants to coverings using defect formulae.
problem Lifting spectral ζ-invariants to coverings of closed manifolds.
method Using lifted defect formulae and Wodzicki residues.
result Derived integrals of Pontryagin and Chern forms for certain lifted spectral ζ-invariants.
Generalizes covering lemmas in metric spaces, finding equivalent properties.
problem Finding equivalent properties of Besicovitch and WBCP in metric spaces.
method Generalization of covering lemmas in complete Riemannian manifolds and Euclidean spaces.
result Equivalence of BCP and WBCP in certain metric spaces.
We classify all closed, aspherical Riemannian manifolds M whose universal cover has indiscrete isometry group. One sample application is the theorem that any such M with word-hyperbolic fundamental group must be isometric to a negatively curved, locally symmetric manifold. Another application is the classification of a…