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arXiv research

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.

168,695 papers · 148 categories

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36912 · Jun 202019922001200920172026
48 results for acute triangles

We study the problem of determining the least symmetric triangle, which arises both from pure geometry and from the study of molecular chirality in chemistry. Using the correspondence between planar nn-gons and points in the Grassmannian of 2-planes in real nn-space introduced by Hausmann and Knutson, this correspond…

2017-08-03abs ↗pdf ↗

The study proves constant-curvature analogues of hot spots conjecture for triangles.

problem Proving the hot spots conjecture in constant curvature domains.
method Analyzing geodesic triangles of constant negative curvature and using Killing fields.
result First mixed Dirichlet-Neumann Laplace eigenfunctions have no non-vertex critical points in constant curvature triangles.

Given a planar compact convex billiard table TT, we give an algorithm to find the shortest generalised closed billiard orbits on TT. (Generalised billiard orbits are usual billiard orbits if TT has smooth boundary.) This algorithm is finite if TT is a polygon and provides an approximation scheme in general. As an i…

2014-08-22abs ↗pdf ↗

Let C(L)C(L) be the right-angled Coxeter group defined by an abstract triangulation LL of S2\mathbb{S}^2. We show that C(L)C(L) is isomorphic to a hyperbolic right-angled reflection group if and only if LL can be realized as an acute triangulation. The proof relies on the theory of CAT(-1) spaces. A corollary is that an …

2013-06-25abs ↗pdf ↗

The paper explores Kähler and anti-Kähler structures on quasi-statistical manifolds.

problem Investigating Kähler and anti-Kähler structures on quasi-statistical manifolds.
method Analyzing conditions for integrability of almost complex structures and defining Kähler and anti-Kähler manifolds.
result Conditions for (Nˊ,h,abla,L)(\acute{N},h, abla ,L) to be an anti-Kähler manifold are identified.

Bayesian optimization improves classifier selection for acute infection and mortality.

problem Improving accuracy of acute infection and mortality prediction.
method Comparison of hyperparameter optimization methods (grid search, random sampling, Bayesian optimization).
result Bayesian optimization outperforms grid search or random sampling for in-hospital mortality classifiers.

New bounds on inscribed triangles in arbitrary planar domains.

problem Finding inscribed triangles in arbitrary planar domains with specific angle constraints.
method Proving the existence of uniformly fat triangles and not-too-fat triangles in bounded open sets.
result Existence of a maximal number Θ (between 0 and 60) for inscribed triangles with angles ≥ Θ degrees.

Paper calculates eigenvalues of a specific triangle on a sphere.

problem Computing eigenvalues of a specific triangle on a sphere.
method Computed first two Dirichlet eigenvalues and eigenfunctions of the equilateral Schwarz triangle (3/2 3/2 3/2) on the sphere.
result Computed the first two Dirichlet eigenvalues and eigenfunctions of the equilateral Schwarz triangle (3/2 3/2 3/2).

Study on Laplacian determinant in isosceles triangles, finding equilateral triangle minimizes determinant.

problem Finding the minimum of the spectral determinant on isosceles triangles.
method Analyzing the determinant of the Laplacian on Euclidean isosceles triangle envelopes of fixed area.
result Equilateral triangle envelope minimizes the determinant of the Laplacian.

The paper classifies Poincaré complexes as topological manifolds.

problem Classifying Poincaré complexes as topological manifolds.
method Using spherical fibrations and CW-complexes, the paper proves stability and homotopy equivalence.
result A sufficient condition for Poincaré complexes to be homotopy types of topological manifolds.

Complex hyperbolic triangle groups were first considered by Mostow in building the first nonarithmetic lattices in PU(2, 1). They are a natural generalization of the classical triangle groups acting on the hyperbolic plane. A well-known theorem of Takeuchi is that there are only finitely many Fuchsian triangle groups t…

2011-09-12abs ↗pdf ↗

It has been shown that the Alvarez-Gaumeˊ\mathrm{\acute{e}}-Witten miraculous anomaly cancellation formula in type IIB superstring theory and its various generalizations can be derived from modularity of certain characteristic forms. In this paper, we show that the Green-Schwarz formula and the Schwarz-Witten formula i…

2012-05-03abs ↗pdf ↗

New surgery exact triangles in Heegaard Floer homology for rational slopes.

problem Constructing new surgery exact triangles in Heegaard Floer homology.
method Combining combinatorial triangle and quadrilateral counting in genus 1 Heegaard diagrams.
result Solving the combinatorial problem for rational slopes, including tricky cases.

Study calculates eigenvalues and eigenfunctions for spherical triangles and finds fundamental gap behavior.

problem Understanding eigenvalues and gaps in spherical triangles.
method Explicit computation of Dirichlet eigenvalues and eigenfunctions for spherical lunes and triangles.
result Fundamental gap of spherical triangles increases as the angle of the lune decreases.

We show that the triangle with angles Pi/12, Pi/3 and 7*Pi/12 has the lattice property and compute this triangle's Veech group.

2011-07-25abs ↗pdf ↗

We study side-lengths of triangles in path metric spaces. We prove that unless such a space X is bounded, or quasi-isometric to line or half-line, every triple of real numbers satisfying the strict triangle inequalities, is realized by the side-lengths of a triangle in X. We construct an example of a complete path metr…

2006-11-06abs ↗pdf ↗

Two triples of triangles having pairwise disjoint outlines in 3-space are called combinatorially isotopic if one triple can be obtained from the other by a continuous motion during which the outlines of the triangles remain pairwise disjoint. We conjecture that it can be algorithmically checked if an (ordered or unorde…

2019-08-11abs ↗pdf ↗

New method proves mateability of triangle groups with Blaschke products.

problem Proving mateability of triangle groups with Blaschke products.
method Associating two piecewise analytic circle maps to the triangle group, mating these with Blaschke products, and constructing a common lift.
result Proves mateability of all cusped triangle groups with suitable Blaschke products.

In this paper we study the area of ideals triangles in a convex domain with its Hilbert geometry. We obtain a characterization of the hyperbolic geometry among all the Hilbert geometry in terms of area of ideals triangles. We also obtain a sharp lower bound on the hilbert area of ideal triangles, independant of the con…

2003-12-08abs ↗pdf ↗

In Lorentzian geometry, limited definition of angles restricts the use of angle bisectors in study of triangles. This paper redefines angle bisectors so that they can be used to study attributes of triangles. Using the new definition, this paper investigates the existence of the incenter and the isogonal conjugate of a…

2014-04-24abs ↗pdf ↗

Study stabilizers of complex hyperbolic triangle groups, finding generators and signatures.

problem Understanding the stabilizers of complex hyperbolic triangle groups.
method Explicit generators and signatures of stabilizers computed for each group orbit of mirrors.
result Explicit generators and signatures of stabilizers for some triangle groups.

Criterion for stopping conjugacy class enumeration in triangle groups.

problem Enumerating all conjugacy classes in cocompact triangle groups.
method Encoding by P. Dehornoy and T. Pinsky; stopping criterion based on geometric length.
result Stopping criterion for the generation of conjugacy classes in cocompact triangle groups.

The paper finds extremum values for mixed Laplacian eigenvalues on triangles and trapezoids.

problem Finding extremum values for mixed eigenvalues of the Laplacian on triangles and trapezoids.
method Characterizations obtained under suitable geometric constraints.
result Characterizations of extremum values for mixed eigenvalues of the Laplacian on triangles and trapezoids.

Study of subgroups in complex hyperbolic lattice triangle groups.

problem Characterizing subgroups of finite index in complex hyperbolic lattice triangle groups.
method Explicit construction and analysis of subgroups, examination of their properties.
result Identification of neat subgroups, subgroups with positive first Betti number, and homomorphisms onto non-Abelian free groups.