The paper shows conflict graphs of Petersen family graphs are mostly unbalanced.
problem Understanding the balance of conflict graphs in Petersen family graphs.
method Analyzing maximally planar subgraphs and their conflict graphs.
result All but three strong conflict graphs from Petersen Family Graphs are unbalanced.
Characterizes groups for Petersen graph embeddings.
problem Identifying symmetry groups of the Petersen graph.
method Analyzes embeddings of the Petersen graph in S^3.
result Characterizes all possible symmetry groups.
New proof shows no flat embedding for Petersen family graphs.
problem Proving Petersen family graphs have no flat embeddings.
method Applying Böhme's Lemma and the Jordan-Brouwer Separation Theorem.
result Every Petersen family graph has no flat embedding.
This paper classifies topological symmetry groups for Petersen family graphs.
problem Understanding symmetries of graphs embedded in 3D space.
method Examined all embeddings of Petersen family graphs in S3 and classified their topological symmetry groups. result Identified all possible groups that can be realized as topological symmetry groups for each graph in the Petersen family.
This paper determines all possible topological symmetry groups of generalized Petersen graphs.
problem Identifying all topological symmetry groups of generalized Petersen graphs.
method Analyzing embeddings of generalized Petersen graphs in S3 and considering homeomorphisms. result All groups that can be topological symmetry groups of generalized Petersen graphs are identified.
Odd crossing numbers and even rotation numbers for cycles in plane immersions.
problem Analyzing crossing and rotation numbers of cycles in plane immersions of graphs.
method Generic immersions and Legendrian embeddings of graphs, focusing on cycles of specific lengths.
result Sum of rotation numbers of all 5-cycles is even, and sum of crossing numbers is odd.
For every spatial embedding of each graph in the Petersen family, it is known that the sum of the linking numbers over all of the constituent 2-component links is congruent to 1 modulo 2. In this paper, we give an integral lift of this formula in terms of the square of the linking number and the second coefficient of t…
This paper focuses on the graphs in the Petersen family, the set of minor minimal intrinsically linked graphs. We prove there is a relationship between algebraic linking of an embedding and knotting in an embedding. We also present a more explicit relationship for the graph K3,3,1 between knotting and linking, whi…
The paper explores linked cycles in graphs and their properties.
problem Understanding the structure of linked cycles in graphs.
method Analyzing the set of all pairs of disjoint cycles in graphs and showing conditions for minimally linked sets.
result A minimally linked set of cycles in a complete graph Kp+q has at most eighteen elements. We examine graphs that contain a non-trivial link in every embedding into real projective space, using a weaker notion of unlink than was used by Flapan, et al. We call such graphs intrinsically linked in projective space. We fully characterize such graphs with connectivity 0,1 and 2. We also show that only one Peterse…
Note proves Petersen-Wilhelm conjecture for positive curvature manifolds.
problem Proving Petersen-Wilhelm conjecture for positive curvature manifolds.
method Considered submersions from compact manifolds homotopy equivalent to Eschenburg or Bazaikin spaces of positive curvature.
result Proves Petersen-Wilhelm conjecture for known compact manifolds with positive curvature.
We show that the 20 graph Heawood family, obtained by a combination of triangle-Y and Y-triangle moves on K7, is precisely the set of graphs of at most 21 edges that are minor minimal for the property not 2--apex. As a corollary, this gives a new proof that the 14 graphs obtained by triangle-Y moves on K7 are t…
Paper studies Wiman-Edge pencil and Wiman curve, providing uniformizations and modular interpretations.
problem Understanding the geometry and uniformization of the Wiman-Edge pencil and Wiman curve.
method Explicit uniformizations of the Wiman-Edge pencil and Wiman curve as quotients of the hyperbolic plane and arithmetic quotients.
result Explicit uniformizations and modular interpretations of the Wiman-Edge pencil and Wiman curve.
Let M be an n-dimensional complete Riemannian manifold with Ricci curvature ≥n−1. In \cite{colding1, colding2}, Tobias Colding, by developing some new techniques, proved that the following three condtions: 1) dGH(M,Sn)→0; 2) the volume of M Vol(M)→Vol(Sn); 3) the radius of $M…
The paper proves a stronger Petersen--Wilhelm conjecture for principal bundles.
problem Conditions for positive sectional curvature submersion metrics on principal bundles.
method Cheeger deformations, good triples, Chaves-Derdzinski-Rigas type condition.
result Any principal bundle over a positively curved base admits a metric of positive sectional curvature if the submersion is fat.
We first show that a Laplace isospectral family of Riemannian orbifolds, satisfying a lower Ricci curvature bound, contains orbifolds with points of only finitely many isotropy types. If we restrict our attention to orbifolds with only isolated singularities, and assume a lower sectional curvature bound, then the numbe…
Proves volume comparison and monotonicity for Bakry-Émery Ricci curvature.
problem Volume comparison and monotonicity for Bakry-Émery Ricci curvature.
method Relative volume comparison theorem for LP-bound of Bakry-Émery Ricci curvature and gradient of potential function. result Modified proof for volume comparison and monotonicity of Kähler-Ricci flow.
New f-vectors reveal geometric Lefschetz-like decompositions of flag spheres.
problem Understanding f-vectors of balanced simplicial complexes and flag spheres. method Analyzing h-vectors and f-vectors of flag spheres and balanced simplicial complexes. result Found f-vectors leading to geometric Lefschetz-like decompositions. Let N be a regular branched cover of a homology 3-sphere M with deck group G isomorphic to Z_2^d and branch set a trivalent graph Gamma; such a cover is determined by a coloring of the edges of Gamma with elements of G. For each index-2 subgroup H of G, M_H = N/H is a double branched cover of M. Sakuma has proved that …
Study improves comparison geometry for spaces with Bakry-Émery Ricci tensor bounds.
problem Improving comparison geometry for spaces with specific Ricci tensor bounds.
method Proved mean curvature and volume comparison estimates on smooth metric measure spaces.
result Generalized diameter, eigenvalue, and volume growth estimates.
The paper finds a pervasive and severe bias in accounting semi-identity models.
problem Bias in investment-cash flow sensitivity models.
method Augmented specification with a bias-capturing variable tested across multiple databases.
result The Accounting Semi-Identity (ASI) distortion is universal and severe, affecting 100% of databases and explaining more than 83% of total explained variance.
In this paper we calculate the curvature of the Hitchin connection. We further show that a slight (possibly trivial) modification of the Hitchin connection has curvature equal to an explict given multiple of the Weil-Petersen symplectic form on Teichmüller space.
Study finds limits on curvature and shape of certain spacetimes.
problem Limits on curvature and shape of compact stationary spacetimes.
method Used Petersen & Wink '21 result on Lorentzian manifolds.
result Obstructions found to curvature and topology of compact spacetimes.
Sphere theorems extended to RCD spaces and improved for Einstein stratified spaces.
problem Generalizing sphere theorems to new types of spaces.
method Proved sphere theorems for RCD(n-1, n) spaces and Einstein stratified spaces.
result Extended sphere theorems to RCD spaces and improved results for Einstein stratified spaces.
We offer the following explanation of the statement of the Kuratowski graph planarity criterion and of 6/7 of the statement of the Robertson-Seymour-Thomas intrinsic linking criterion. Let us call a cell complex 'dichotomial' if to every cell there corresponds a unique cell with the complementary set of vertices. Then …
Paper extends curvature estimates to new tensor types.
problem Mean curvature and volume comparison estimates for integral generalized quasi-Einstein tensors.
method Extends existing comparison results to new tensor types.
result Global diameter estimates derived from comparison results.
Sphere theorem extended without Ricci curvature positivity.
problem Eigenvalue pinching under Ricci curvature bounds.
method Generalization of Petersen and Aubry's sphere theorem.
result Eigenvalue pinching achieved without Ricci curvature positivity.
Study characterizes Einstein metrics in warped product spaces.
problem Characterizing Einstein metrics in warped product spaces.
method Local characterizations and global restatements of known results.
result Restated global characterizations of Einstein manifolds.
Upper bounds on Betti numbers via curvature constraints.
problem Bounding Betti numbers of Riemannian manifolds.
method Integral bounds on curvature eigenvalues, Bochner technique.
result New curvature condition for vanishing Betti numbers.
Classifies spaces with positive curvature and small boundary.
problem Understanding spaces with positive curvature and small boundary.
method Analyzes Alexandrov spaces with lower curvature bound 1 and small boundary.
result Classifies the total space X when the radius is π/2 and the boundary has diameter π/2.
Study pinching constants for Kähler manifolds with positive curvature.
problem Pinching constants of Kähler manifolds with positive holomorphic sectional curvature.
method Apply techniques from Riemannian pinching theory to Kähler geometry.
result Prove a gap theorem for Kähler manifolds with almost quarter-pinched holomorphic sectional curvature.
We introduce the tractor formalism from conformal geometry to the study of smooth metric measure spaces. In particular, this gives rise to a correspondence between quasi-Einstein metrics and parallel sections of certain tractor bundles. We use this formulation to give a sharp upper bound on the dimension of the vector …
The reflection length of an element of a Coxeter group is the minimal number of conjugates of the standard generators whose product is equal to that element. In this paper we prove the conjecture of McCammond and Petersen that reflection length is unbounded in any non-affine Coxeter group. Among the tools used, the con…
The paper studies rigidity results for harmonic forms on Kähler manifolds.
problem Understanding harmonic forms on Kähler manifolds.
method Analyzes rigidity results for harmonic (p,q)-forms in complete Kähler manifolds. result Shows several rigidity results and applications to non-compact Kähler manifolds.
Study quantifies convergence of Alexandrov spaces without collapsing.
problem Quantifying convergence of Alexandrov spaces without collapsing.
method Lipschitz homotopy convergence for Alexandrov spaces.
result Lipschitz homotopies can be chosen to preserve singular strata.
Estimates radius and volume of curved spaces with convex boundaries.
problem Estimating the radius and volume of curved spaces with convex boundaries.
method Analyzes Alexandrov spaces with strictly convex boundaries, using Base-Angle and volume estimates.
result Estimates for radius and volume of curved spaces with convex boundaries.
Study Gromov-Hausdorff convergence of metric pairs and tuples.
problem Understanding convergence in metric spaces.
method Prove equivalence of definitions, embedding, completeness, and compactness theorems.
result Relative version of Fukaya's theorem and finiteness theorem for stratified spaces.
The paper classifies quasi-Einstein manifolds with harmonic Weyl curvature.
problem Classifying quasi-Einstein manifolds with specific curvature properties.
method Extending and refining previous work on quasi-Einstein manifolds, focusing on harmonic Weyl curvature.
result New examples of quasi-Einstein manifolds are provided, which are neither locally conformally flat nor D-flat.
We show that a complete Riemannian manifold of dimension n with $\Ric\geq n{-}1$ and its n-st eigenvalue close to n is both Gromov-Hausdorff close and diffeomorphic to the standard sphere. This extends, in an optimal way, a result of P. Petersen. We also show that a manifold with $\Ric\geq n{-}1$ and volume close…
New proof of shrinking gradient Ricci soliton rigidity.
problem Rigidity of shrinking gradient Ricci solitons.
method Maximum principle, maximum curvature condition.
result Shrinking gradient Ricci soliton with constant scalar curvature is isometric to a finite quotient of R^2 x S^2.
Simplified proof of stability for Ricci flow near ALE metrics.
problem Stability of Ricci flow near ALE metrics with integrable deformations.
method Equivalence between integrability and almost-orthogonality property of Ricci-DeTurck tensor, analysis in weighted Holder spaces.
result Dynamical stability of Ricci flow near linearly stable Ricci-flat ALE metrics.
We show that for n dimensional manifolds whose the Ricci curvature is greater or equal to n-1 and for k in {1,...,n+1}, the k-th eigenvalue for the Laplacian is close to n if and only if the manifold contains a subset which is Gromov-Hausdorff close to the unit sphere of dimension k-1. For k=n+1, this gives a new proof…
The study generalizes curvature bounds for manifolds with boundary.
problem Proving curvature bounds for manifolds with boundary.
method Bakry-Émery curvature bounds and splitting theorems.
result Proves curvature bounds for manifolds with boundary.
Establishes metrics with positive 2nd intermediate Ricci curvature on products of curved spaces.
problem Examines the limitations of positive curvature metrics on product spaces.
method Uses examples to show Ric2>0 does not imply positive curvature for products of spaces. result The Ric2>0 class of manifolds is distinct from positively curved manifolds. We give a characterization of critical points that allows us to define a metric invariant on all Riemannian manifolds M with a lower sectional curvature bound and an upper radius bound. We show there is a uniform upper volume bound for all such manifolds with an upper bound on this invariant. We generalize results by…
In this article we study homogeneous warped product Einstein metrics and its connections with homogeneous Ricci solitons. We show that homogeneous (λ,n+m)-Einstein manifolds (which are the bases of homogeneous warped product Einstein metrics) are one-dimensional extensions of algebraic solitons. This answers a questi…
New examples show strong Kato limits can be branching and not satisfy known conditions.
problem Exploring the boundaries of strong Kato limits and their properties.
method Constructing specific examples of non-collapsed strong Kato limits.
result Found examples of strong Kato limits that are branching and do not satisfy CD(K,∞) or MCP(K,N) conditions. We say that a nonnegatively curved manifold (M,g) has quarter pinched flag curvature if for any two planes which intersect in a line the ratio of their sectional curvature is bounded above by 4. We show that these manifolds have nonnegative complex sectional curvature. By combining with a theorem of Brendle and Schoe…