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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.

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371013 · Apr 202619922001200920172026
48 results for thin triangles

In this paper we explore the idea that Teichmüller space is hyperbolic "on average." Our approach focuses on studying the geometry of geodesics which spend a definite proportion of time in some thick part of Teichmüller space. We consider several different measures on Teichmüller space and find that this behavior for g…

2011-08-27abs ↗pdf ↗

We describe a procedure which verifies that a group given by generators and relators is word-hyperbolic. This procedure always works with a group which is word-hyperbolic, provided there is sufficient memory and time devoted to the problem. If the group is not word-hyperbolic, the procedure continues indefinitely. We a…

1998-11-03abs ↗pdf ↗

Quasi-alternating links are a natural generalization of alternating links. In this paper, we show that quasi-alternating links are "homologically thin" for both Khovanov homology and knot Floer homology. In particular, their bigraded homology groups are determined by the signature of the link, together with the Euler c…

2007-08-23abs ↗pdf ↗

The paper extends the collar theorem to non-compact surfaces using new comparison theorems.

problem Proving the collar theorem for non-compact surfaces.
method Developed new Toponogov-type triangle comparison theorems.
result Eliminated the compactness hypothesis for the collar theorem.

We study Kauffman's model of folded ribbon knots: knots made of a thin strip of paper folded flat in the plane. The ribbonlength is the length to width ratio of such a ribbon, and it turns out that the way the ribbon is folded influences the ribbonlength. We give an upper bound of ncot(π/n)n\cot(π/n) for the ribbonlength of $…

2016-02-25abs ↗pdf ↗

We show that simple random walks on (non-trivial) relatively hyperbolic groups stay O(log(n))O(\log(n))-close to geodesics, where nn is the number of steps of the walk. Using similar techniques we show that simple random walks in mapping class groups stay O(nlog(n))O(\sqrt{n\log(n)})-close to geodesics and hierarchy paths. Along the…

2013-05-23abs ↗pdf ↗

The paper examines rigidity of thin domains under specific boundary conditions.

problem Linear geometric rigidity of shallow thin domains with zero Dirichlet boundary conditions.
method Analyzes two scaling regimes for ε in (h, √h] and (√h, 1), proving rigidity formulas.
result Rigidity does not depend on curvature in the small parameter regime ε ∈ (h, √h].

We define a new notion of thin position for a graph in a 3-manifold which combines the ideas of thin position for manifolds first originated by Scharlemann and Thompson with the idea of thin position for knots first originated by Gabai. This thin position has the property that connect summing annuli and pairs-of-pants …

2016-06-10abs ↗pdf ↗

Let k be a knot in S3. In [8], H.N. Howards and J. Schultens introduced a method to construct a manifold decomposition of double branched cover of (S3, k) from a thin position of k. In this article, we will prove that if a thin position of k induces a thin decomposition of double branched cover of (S3,k) by Howards and…

2010-01-06abs ↗pdf ↗

Abby Thompson proved that if a link KK is in thin position but not in bridge position then the knot complement contains an essential meridional planar surface, and she asked whether some thin level surface must be essential. This note is to give a positive answer to this question, showing that the if a link is in thin…

2006-10-27abs ↗pdf ↗

New method characterizes thin links via Conway spheres and tangle decompositions.

problem Characterize thin links without relying on specific knot invariants.
method Developed a relative version of thinness for tangles and used it to characterize thinness via tangle decompositions along Conway spheres.
result Characterized thin links via Conway spheres and tangle decompositions.

Data thinning splits observations into independent parts for convolution-closed distributions.

problem Validation of unsupervised learning results in settings with limited data.
method Data thinning, splitting observations into independent parts following the same distribution.
result Data thinning provides an attractive alternative to cross-validation in settings with limited sample splitting.

Kernel thinning compresses distributions more effectively than i.i.d. sampling or standard thinning.

problem Efficiently compressing distributions for better sampling and integration accuracy.
method Introduces kernel thinning, a procedure that compresses an n-point approximation of a distribution into a sqrt(n)-point approximation with comparable integration error.
result Kernel thinning achieves a maximum discrepancy in integration error of O_d(n^(-1/2) sqrt(log n)) in probability for compactly supported distributions and O_d(n^(-1/2) (log n)^(d+1/2) sqrt(log log n)) for sub-exponential distributions.

Wu has shown that if a link or a knot LL in S3S^3 in thin position has thin spheres, then the thin sphere of lowest width is an essential surface in the link complement. In this paper we show that if we further assume that LS3L \subset S^3 is prime, then the thin sphere of lowest width also does not have any vertical c…

2008-01-12abs ↗pdf ↗

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.

We show that every thin position for a connected sum of small knots is obtained in an obvious way: place each summand in thin position so that no two summands intersect the same level surface, then connect the lowest minimum of each summand to the highest maximum of the adjacent summand below.

2002-05-12abs ↗pdf ↗

Let L be a link in the 3-sphere that is in thin position but not in bridge position and let P be a thin level sphere. We generalize a result of Wu by giving a bound on the number of disjoint irreducible compressing disks that P can have, including identifying thin spheres with unique compressing disks. We also give con…

2004-04-15abs ↗pdf ↗

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 ↗

In this paper, we give an algorithm to build all compact orientable atoroidal Haken 3-manifolds with tori boundary or closed orientable Haken 3-manifolds, so that in both cases, there are embedded closed orientable separating incompressible surfaces which are not tori. Next, such incompressible surfaces are related to …

2015-11-03abs ↗pdf ↗

In this paper we produce many examples of thin subgroups of special linear groups that are isomorphic to the fundamental groups of non-arithmetic hyperbolic manifolds. Specifically, we show that the non-arithmetic lattices in SO(n,1)\mathrm{SO}(n,1) constructed by Gromov and Piatetski-Shapiro can be embedded into $\mathrm{S…

2019-11-16abs ↗pdf ↗

We introduce a method for creating a special type of tree, called a tree position, from a weighted graph. Leaves of the tree correspond to vertices of the original graph, and the tree edges contain information which can be used to partition these vertices. By repeatedly applying reducing operations to the tree position…

2014-08-15abs ↗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.

We generalize the definition of thin position of Scharlemann and Thompson for compact orientable 3-manifolds with torus boundary components and introduce αα-sloped generalized Heegaard splittings. We examine its relationship to generalized Heegaard splittings of manifolds resulting from Dehn filling. We compare alpha-…

2011-02-15abs ↗pdf ↗