A locally-built, LLM-digested index of recent arXiv papers in quant finance, geometry/topology, and statistical ML — keyword search served straight from SQLite on this machine.
In this paper we study properties of the area evolute (AE) and the center symmetry set (CSS) of a convex planar curve γ. The main tool is to define a Minkowski plane where γ becomes a constant width curve. In this Minkowski plane, the CSS is the evolute of γ and the AE is an involute of the CSS. We prove that the…
Given a Riemannian metric on a homotopy n-sphere, sweep it out by a continuous one-parameter family of closed curves starting and ending at point curves. Pull the sweepout tight by, in a continuous way, pulling each curve as tight as possible yet preserving the sweepout. We show: Each curve in the tightened sweepout …
A number of results for C2-smooth surfaces of constant width in Euclidean 3-space E3 are obtained. In particular, an integral inequality for constant width surfaces is established. This is used to prove that the ratio of volume to cubed width of a constant width surface is reduced by shrinking it along…
We give a simple procedure to estimate the smallest Lipshitz constant of a degree 1 map from a Riemannian 2-sphere to the unit 2-sphere, up to a factor of 10. Using this procedure, we are able to prove several inequalities involving this Lipshitz constant. For instance, if the smallest Lipshitz constant is at least 1, …
For negatively curved manifolds, a condition is found for intrinsic ultracontractivity of heat semigroups.
problem Investigating intrinsic ultracontractivity for domains in negatively curved manifolds.
method Using volume doubling property, Poincaré inequality, and Li-Yau Gaussian estimate for the Dirichlet heat kernel.
result The reciprocal of the bottom of the spectrum and the supremum of the torsion function are comparable with the square of the capacitary width for small capacitary width.
We present an alternative proof of the following fact: the hyperspace of compact closed subsets of constant width in Rn is a contractible Hilbert cube manifold. The proof also works for certain subspaces of compact convex sets of constant width as well as for the pairs of compact convex sets of constant rela…
We prove that among all constant width bodies of revolution, the minimum of the ratio of the volume to the cubed width is attained by the constant width body obtained by rotation of the Reuleaux triangle about an axis of symmetry.
In 1926 S. Nakajima (= A. Matsumura) showed that any convex body in R3 with constant width, constant brightness, and boundary of class C2 is a ball. We show that the regularity assumption on the boundary is unnecessary, so that balls are the only convex bodies of constant width and brightness.
Let n be a natural number equal or greater than 2. In this paper we study the topological structure of certain hyperspaces of convex subsets of constant width, equipped with the Hausdorff metric topology. We focus our attention on the hyperspace cw_D(R^n) of all compact convex subsets with constant width d\in D, where …
Motivated by the theory of quantum waveguides, we investigate the spectrum of the Laplacian, subject to Dirichlet boundary conditions, in a curved strip of constant width that is defined as a tubular neighbourhood of an infinite curve in a two-dimensional Riemannian manifold. Under the assumption that the strip is asym…
A simple closed curve γ in the real projective plane P2 is called anti-convex if for each point p on the curve, there exists a line which is transversal to the curve and meets the curve only at p. We shall prove the relation i(γ)−2δ(γ)=3 for anti-convex curves, where i(γ) is the number of independent (true…
Consider a convex polygon P in the plane, and denote by U a homothetical copy of the vector sum of P and (-P). Then the polygon U, as unit ball, induces a norm such that, with respect to this norm, P has constant Minkowskian width. We define notions like Minkowskian curvature, evolutes and involutes for polygons of con…
There are many "minimax" complexity functions in mathematics: width of a tree or a link, Heegaard genus of a 3-manifold, the Cheeger constant of a Riemannian manifold. We define such a function w, "width", on countable (or finite) groups and show w(Z^k) = k-1.
Lower bound for Steklov eigenvalues on negatively curved manifolds.
problem Finding a geometric lower bound for the first nonzero Steklov eigenvalue.
method Combining a uniform lower bound for the first eigenvalue of the Steklov-Dirichlet problem and a tubular neighborhood theorem for totally geodesic hypersurfaces.
result A geometric lower bound for the first nonzero Steklov eigenvalue in terms of total and boundary volumes.
We provide an upper bound for the Gromov width of compact homogeneous Hodge manifolds (M,ω) with b2(M)=1. As an application we obtain an upper bound on the Seshadri constant ε(L) where L is the ample line bundle on M such that c1(L)=[πω].
We investigate several integer invariants of curves in 3-space. We demonstrate relationships of these invariants to crossing number and to total curvature.
The width of a closed convex subset of Euclidean space is the distance between two parallel supporting planes. The Blaschke-Lebesgue problem consists of minimizing the volume in the class of convex sets of fixed constant width and is still open in dimension n > 2. In this paper we describe a necessary condition that th…
Wider neural networks perform better than deeper ones with the same number of parameters.
problem Understanding the role of network width versus the number of parameters in neural network performance.
method Comparing models with different ways of increasing width while keeping the number of parameters constant, analyzing their performance and using Gaussian Process kernels for analysis.
result Network width is the determining factor for good performance, while the number of weights is secondary as long as trainability is ensured.