Smooth manifolds from locally homogeneous spaces.
problem Understanding smoothness in C0-Riemannian manifolds. method Demonstrated locally homogeneous C0-Riemannian manifolds are smooth. result Locally homogeneous C0-Riemannian manifolds are smooth. Smooth Riemannian manifolds can be embedded without boundary.
problem Embedding smooth Riemannian manifolds with boundary into complete manifolds without boundary.
method General gluing and conformal-deformation construction.
result Any smooth, metrically complete Riemannian manifold with smooth boundary can be realized as a closed domain into a smooth, geodesically complete Riemannian manifold without boundary.
We construct a natural co-Riemannian structure on the manifold of smooth loops in a Riemannian manifold. We show that the smooth loop space of a string manifold is a per-Hilbert-Schmidt locally equivalent co-spin manifold and thus admits a Dirac operator.
Riemannian metrics and Laplacians defined for complex distributions on manifolds.
problem Defining metrics and Laplacians for distributions on manifolds of varying rank.
method Introduced a Riemannian metric and Laplace operator for generalised smooth distributions on manifolds.
result Essentially self-adjoint Laplacian on compact manifolds, hypoellipticity proven.
Smooth projections on manifolds split into simpler parts.
problem Decomposing operators on Riemannian manifolds.
method Constructing a sum of smooth orthogonal projections.
result Extends decomposition on real line to manifolds.
Smooth solutions found for modified mean curvature flow in Riemannian manifolds.
problem Existence of smooth solutions for modified mean curvature flow.
method A priori estimates for modified mean curvature flow in Riemannian manifolds with Killing vector field.
result Existence of smooth, entire, longtime solutions for modified mean curvature flow with smooth initial data.
Proof shows smooth minimal hypersurfaces for perimeter-minimizing sets in low-dimensional Riemannian manifolds.
problem Finding sets of least perimeter in Riemannian manifolds.
method Short proof using de Giorgi and Miranda's tradition in flat space.
result Reduced boundary of least perimeter sets is a smooth minimal hypersurface in low dimensions.
Survey on gluing constructions under lower curvature bounds.
problem Understanding lower curvature bounds in various geometric contexts.
method Analyzes gluing constructions in smooth and non-smooth settings.
result Provides conjectures and theorems on synthetic lower Ricci curvature bounds.
Survey on smooth function and form density in Riemannian Sobolev spaces.
problem Density of smooth functions and forms in Sobolev spaces on Riemannian manifolds.
method Careful examination of weak covariant derivatives and partial derivatives.
result Equivalence of weak covariant derivatives to weak partial derivatives.
The study extends calibrated geometry to smooth maps and finds energy bounds.
problem Finding energy bounds for smooth maps between Riemannian manifolds.
method Generalizing calibrated submanifolds to smooth maps and applying to energy functional.
result Lower bounds to the energy of smooth maps in homotopy classes.
Let M be a differentiable manifold. We say that a tensor field g defined on M is non-regular if g is in some local Lp space or if g is continuous. In this work we define a mollifier smoothing g_t of g that has the following feature: If g is a Riemannian metric of class C2, then the Levi-Civita connection and the Rieman…
Riemannian gradient descent helps escape saddle points on curved spaces.
problem Minimizing nonconvex functions on curved spaces (Riemannian manifolds).
method Perturbed Riemannian gradient descent algorithm.
result Converges to second-order stationary points, matching unconstrained smooth minimization rates.
The study proves smoothness and estimates for p-harmonic mappings between Riemannian manifolds.
problem Smoothness and estimates for p-harmonic mappings between Riemannian manifolds. method Analyzing stationary and minimizing p-harmonic mappings with specific curvature conditions. result Smoothness and estimates for p-harmonic mappings under certain curvature conditions. We establish combinatorial versions of various classical systolic inequalities. For a smooth triangulation of a closed smooth manifold, the minimal number of edges in a homotopically non-trivial loop contained in the 1-skeleton gives an integer called the combinatorial systole. The number of top-dimensional simplices…
Smooth submetries between curved spaces are smooth.
problem Smoothness of submetries between curved spaces.
method Proving smoothness of submetries in a general setting, including Riemannian submersions and isometric actions.
result Smoothness of the base manifold is implied by the smoothness of the total manifold without curvature assumptions.
New obstruction found for smoothability of certain 4-manifolds.
problem Obstructing the smoothability of Riemannian metrics with non-positive sectional curvature.
method Extending Davis-Januszkiewicz-Lafont methods to construct examples of locally CAT(0) 4-manifolds with specific properties.
result Examples of locally CAT(0) 4-manifolds that do not have a Riemannian smoothing despite satisfying isolated flats condition.
We show that for every Lipschitz function f defined on a separable Riemannian manifold M (possibly of infinite dimension), for every continuous ε:M→(0,+∞), and for every positive number r>0, there exists a C∞ smooth Lipschitz function g:M→R such that ∣f(p)−g(p)∣≤ε(p) for every …
Smooth families of biholomorphisms between strongly pseudoconvex domains are shown to be smooth.
problem Smoothness of families of biholomorphisms between strongly pseudoconvex domains.
method Riemannian geometry of Bergman metrics and smoothness of families of isometries.
result Smoothness of families of biholomorphisms between strongly pseudoconvex domains.
Generic smooth boundaries for isoperimetric regions in 8D manifolds.
problem Understanding boundaries of isoperimetric regions in high-dimensional spaces.
method Generic regularity results for isoperimetric regions in closed Riemannian manifolds of dimension eight.
result Smooth nondegenerate boundaries for isoperimetric regions for generic metrics and volumes.
Smooth approximation of integral cycles mod 2 in Riemannian manifolds.
problem Approximating mod 2 integral cycles by smooth submanifolds.
method Approximation of mod 2 integral cycles by smooth submanifolds with controlled singularities.
result Every mod 2 integral cycle can be approximated by a smooth submanifold with a controlled singular set.
We establish a second order smooth variational principle valid for functions defined on (possibly infinite-dimensional) Riemannian manifolds which are uniformly locally convex and have a strictly positive injectivity radius and bounded sectional curvature.
Proves stable smooth minimal hypersurface for trapped region boundary in large dimensional manifolds.
problem Boundary stability of trapped region in large dimensional manifolds.
method Analyzes asymptotically Euclidean Riemannian manifolds of dimension at least 3.
result Boundary is a stable smooth minimal hypersurface except for a singular set of codimension at least 8.
Study rough Riemannian metrics on manifolds, proving their connectedness and completeness.
problem Understanding the space of all locally elliptic and bounded Riemannian metrics on manifolds.
method Introduced an extended metric space and proved its properties.
result Proved the space of rough Riemannian metrics is complete and connected.
Develops calculus on Wasserstein spaces for Riemannian manifolds.
problem Characterizing and understanding the geometry of Wasserstein spaces.
method Intrinsic formalism for topology, smooth structure, and Riemannian geometry of Wasserstein spaces.
result Wasserstein spaces of closed manifolds are geodesically convex.
We begin by showing that every real analytic orbifold has a real analytic Riemannian metric. It follows that every reduced real analytic orbifold can be expressed as a quotient of a real analytic manifold by a real analytic almost free action of a compact Lie group. We then extend a well-known result of Nomizu and Ozek…
The paper investigates exotic smooth structures on manifolds with group actions.
problem Existence of homeomorphic but not diffeomorphic smooth manifolds with shared basic spectra.
method Investigates Riemannian Laplacian eigenvalues and eigenfunctions on manifolds with compact Lie group actions.
result Establishes the existence of homeomorphic yet not diffeomorphic manifolds with shared basic spectra.
We prove here that given a proper isometric action K×M→M on a complete Riemannian manifold M then every continuous isometric flow on the orbit space M/K is smooth, i.e., it is the projection of an K-equivariant smooth flow on the manifold M. As a direct corollary we infer the smoothness of isometric …
Let Mn be a complete, non-compact and C∞-smooth Riemannian manifold with nonnegative sectional curvature. Suppose $\Cal S$ is a soul of Mn. Then any distance non-increasing retraction $Ψ: M^n \to \Cal S$ must give rise to a C∞-smooth Riemannian submersion.
Smooth approximations of Lipschitz maps via Ehresmann fibrations and Reeb sphere theorem for functions.
problem Approximating Lipschitz maps and understanding singular points in Riemannian manifolds.
method Using Ehresmann fibrations and Reeb's sphere theorem for Lipschitz functions.
result A Lipschitz map can be approximated by a smooth map via Ehresmann fibrations.
Locally homogeneous RCD spaces are shown to be smooth manifolds.
problem Understanding the structure of RCD spaces.
method Adapting existing results to new spaces.
result Locally homogeneous RCD spaces are isometric to smooth manifolds.
Smooth approximation of integral cycles in manifolds.
problem Approximating integral cycles in Riemannian manifolds.
method Approximation of integral cycles by smooth submanifolds with controlled area and singularities.
result Integral cycles can be approximated by smooth submanifolds with controlled area and singularities.
Let M be a Riemannian manifold with a polar action by the Lie group G, with section Σ⊂M and generalized Weyl group W. We show that restriction to Σ is a surjective map from the set of smooth G-invariant tensors on M onto the set of smooth W-invariant tensors on Σ. Moreover, we show that every s…
The paper proves estimates for solutions to nonlinear equations on manifolds with boundary.
problem Boundary estimates for fully nonlinear Yamabe equations on Riemannian manifolds.
method Deriving a priori second derivative estimates for subsolutions.
result Existence of smooth solutions with uniform estimates.
The paper extends geometric inequalities from Euclidean space to Riemannian manifolds.
problem Proving geometric inequalities on smooth oriented Riemannian manifolds.
method Introducing symmetric decreasing rearrangement inequalities and testing their applicability to Riemannian manifolds.
result Smooth co-area formula and re-formulated geometric inequalities on Riemannian manifolds.
The paper studies convergence of discrete harmonic maps to smooth ones.
problem Discretization of harmonic maps between Riemannian manifolds.
method Introducing triangulations with vertex and edge weights, and studying convergence conditions.
result Suitable conditions on weighted triangulations ensure convergence of discrete harmonic maps to smooth ones.
New proof shows travel time differences on boundary uniquely identify Riemannian manifold.
problem Identifying Riemannian manifolds from boundary travel time differences.
method New proof with weaker boundary condition.
result Riemannian manifold uniquely determined from boundary travel time differences.
Study on heat trace on sub-Riemannian manifolds using probabilistic methods.
problem Analyzing heat trace on sub-Riemannian manifolds with smooth measures.
method Probabilistic approach using S. Watanabe's distributional Malliavin calculus.
result Proved a short time asymptotic expansion of the heat trace up to any order.
We smooth the singularities of a strictly hyperbolized smooth cube manifold.
The paper proves rigidity of scalar curvature on Riemannian manifolds.
problem Proving rigidity of scalar curvature on Riemannian manifolds.
method Analyzes conformal metrics and scalar curvature conditions.
result Proves rigidity of the metric on certain domains.
The study connects polyhedral manifolds to Riemannian ones with geometric bounds.
problem Connecting polyhedral manifolds to Riemannian manifolds with geometric constraints.
method Using a theorem by C. Lange and B. Bowditch, the study bounds the curvature and injectivity radius of Riemannian manifolds.
result Polyhedral manifolds with bounded geometry are bi-Lipschitz homeomorphic to Riemannian manifolds with controlled curvature and injectivity radius.
New subharmonicity concept proves conjecture on Riemannian manifolds.
problem Proving positivity of solutions to a specific PDE on Riemannian manifolds.
method Introducing local λ-shift defectivity and studying it on locally smoothing spaces. result Proof of Braverman, Milatovic, Shubin conjecture on positivity of solutions.
Smooth bundles with rough data maintain Hodge kernel isomorphism.
problem Maintaining Hodge kernel isomorphism for smooth bundles with non-smooth geometric data.
method Analyzing nilpotent differential operators and Hodge-Dirac-type operators under perturbations of geometric data.
result Kernels of Hodge-Dirac operators remain isomorphic under uniform perturbations of geometric data.
Study solves Gel'fand's inverse problem in non-smooth spaces with Ricci curvature bounds.
problem Determining a Riemannian manifold from heat kernel on subsets.
method Analyzes mRCD(K,N) spaces with synthetic Ricci curvature bounds. result Unique solvability of Gel'fand's inverse problem for compact mRCD(K,N) spaces. The study proves a compactness theorem for manifolds with specific curvature conditions.
problem Proving compactness theorems for manifolds with Bakry-Emery Ricci tensor.
method Using Bakry-Emery Ricci tensor and smooth measure.
result Generalized Myers compactness theorem proved.
New heat dispersion laws established for smooth compact manifolds.
problem Understanding heat dispersion in smooth compact manifolds.
method Established new heat dispersion laws through Theorem 1.1 and explored them further with Propositions 3.1 and 3.2.
result New heat dispersion laws for smooth compact manifolds.
Smooth metrics satisfying Penrose inequality are necessarily smooth.
problem Rigidity of Penrose inequality with singular metrics.
method Showed suitable singular metrics attaining the optimal value in the Riemannian Penrose inequality are smooth in specified coordinates.
result Smooth metrics satisfying Penrose inequality are necessarily smooth.
The paper explores complex Poisson structures on smooth functions in complex manifolds.
problem Exploring complex Poisson structures on smooth functions in complex manifolds.
method Considering structures of complex Poisson brackets generated by a (1,1)-form. result Examples of complex Poisson structures are provided in $\C^\ast$.
Theory of covariant Schrödinger semigroups on Riemannian manifolds developed.
problem Developing theory for Schrödinger semigroups on Riemannian manifolds.
method Sobolev spaces, heat kernels, differential operators, Wiener measure, Dynkin and Kato potentials.
result Properties and continuity of covariant Schrödinger semigroups established.