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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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48 results for conjugate radius

Upper bound for conjugate radius in open manifolds with scalar curvature and spectrum constraints.

problem Bounding the conjugate radius of open manifolds with specific curvature and spectrum conditions.
method Established an upper bound using scalar curvature and bottom-of-spectrum constraints.
result For certain conditions, the conjugate radius is no more than π.

Upper bound on Stiefel manifold's injectivity radius found.

problem Finding the maximum distance within which the Stiefel manifold remains injective.
method Exhibited conjugate points and calculated the minimum of geodesic lengths.
result Upper bound on Stiefel manifold's injectivity radius is conjectured to be equal to the injectivity radius.

Characterizes bi-Perron numbers with specific Galois conjugates.

problem Understanding bi-Perron numbers with real or unimodular conjugates.
method Characterization through power properties and spectral radii of transformations.
result Bi-Perron numbers with real or unimodular conjugates admit a power as stretch factors or spectral radii.

Study dispersive estimates for Schrödinger and wave equations on a cone with specific metric.

problem Pointwise decay estimates for Schrödinger and wave equations on a product cone.
method Modified Hadamard parametrix on YY with ε>πε > π to prove dispersive estimates.
result Threshold of conjugate radius ε>πε > π for pointwise dispersive estimates.

The ratio of convexity radius over injectivity radius may be made arbitrarily small within the class of compact Riemannian manifolds of any fixed dimension at least two. This is proved using Gulliver's method of constructing manifolds with focal points but no conjugate points. The approach is suggested by a characteriz…

2014-12-01abs ↗pdf ↗

The paper studies conjugate points on Lie groups with specific metrics.

problem Existence and properties of conjugate points on Lie groups with left-invariant metrics.
method Using reformulated index form in terms of adjoint action, the paper proves sufficient conditions for conjugate points and provides bounds and criteria.
result All geodesics in compact semisimple Lie groups have conjugate points, with upper and lower bounds on conjugate times.

In this paper, we prove that, for any integer n2,n\ge 2, there exists an εn0ε_{n} \ge 0 so that if MM is an n-dimensional complete manifold with sectional curvature KM1 K_{M}\ge 1 and if MM has conjugate radius bigger than π2\fracπ{2} and contains a geodesic loop of length 2(πεn),2(π-ε_{n}), then MM is diffeomorphic to the…

2004-07-08abs ↗pdf ↗

A well-known Lemma in Riemannian geometry by Klingenberg says that if x0x_0 is a minimum point of the distance function d(p,)d(p,\cdot) to pp in the cut locus CpC_p of pp, then either there is a minimal geodesic from pp to x0x_0 along which they are conjugate, or there is a geodesic loop at pp that smoothly goes throu…

2014-01-22abs ↗pdf ↗

We derive a uniform bound for the total betti number of a closed manifold in terms of a Ricci curvature lower bound, a conjugate radius lower bound and a diameter upper bound. The result is based on an angle version of Toponogov comparison estimate for small triangles in a complete manifold with a Ricci curvature lower…

1994-11-07abs ↗pdf ↗

A pseudo-Anosov surface automorphism φφ has associated to it an algebraic unit λφλ_φ called the dilatation of φφ. It is known that in many cases λφλ_φ appears as the spectral radius of a Perron-Frobenius matrix preserving a symplectic form LL. We investigate what algebraic units could potentially appear as dilatatio…

2011-04-13abs ↗pdf ↗

The paper counts conjugacy classes of pseudo-Anosov homeomorphisms in Teichmüller space.

problem Counting conjugacy classes of pseudo-Anosov homeomorphisms in Teichmüller space.
method Analyzes the asymptotic behavior of conjugacy classes as the radius of a ball in Teichmüller space increases.
result Asymptotics for the number of pseudo-Anosov homeomorphisms conjugate to a given homeomorphism within a ball of radius R centered at X.

The study examines how average scalar curvature influences geometric properties of Riemannian manifolds.

problem Investigating the geometric properties of Riemannian manifolds influenced by average scalar curvature.
method Analyzing the conjugate radius, average area of geodesic spheres, average volume of metric balls, and total volume of closed manifolds.
result Improves the Bishop-Gromov estimate on the average volume of metric balls and proves monotone decreasing properties of certain geometric integrals.

The paper proves finite topological type theorems for open manifolds with non-negative Ricci curvature and almost maximal local rewinding volume.

problem Proving finite topological type theorems for open manifolds with non-negative Ricci curvature and almost maximal local rewinding volume.
method The approach removes constraints of sectional curvature or conjugate radius and extends to previous related studies.
result Theorems are proven for open manifolds with non-negative Ricci curvature and almost maximal local rewinding volume, without the need for triangle comparison of Toponogov type.

The study examines the growth of conjugacy classes in negatively curved manifolds.

problem Growth of conjugacy classes in manifolds with variable negative curvature.
method Analyzes the number of conjugacy class orbits in a ball of radius T centered at a point in the universal cover of a manifold.
result Exponentially small error terms for the count of conjugacy class orbits in 2D or high-dimensional manifolds with specific curvature bounds.

Let M be a complete Riemannian manifold whose sectional curvature is bounded above by 1. We say that M has positive spherical rank if along every geodesic one hits a conjugate point at t=π. The following theorem is then proved: If M is a complete, simply connected Riemannian manifold with upper curvature bound 1 and po…

2003-05-12abs ↗pdf ↗

The paper tackles efficient computation of optimal transport by approximating conjugates with amortized optimization.

problem Efficient computation of convex conjugates in optimal transport is challenging and limits the quality of transport maps.
method The approach combines amortized approximations of conjugates with a fine-tuning solver to improve transport map quality.
result The method significantly improves the quality of transport maps for the Wasserstein-2 benchmark and models many 2D couplings and flows.

New method speeds up inference for non-conjugate Gaussian processes.

problem Inference for non-conjugate Gaussian processes is slow and unreliable.
method Automated augmented conjugate inference method that constructs auxiliary variables to make the model conditionally conjugate.
result Our method is up to two orders of magnitude faster and more robust than existing methods.

We introduce a multiple conjugation biquandle, and show that it is the universal algebra to define a semi-arc coloring invariant for handlebody-links. A multiple conjugation biquandle is a generalization of a multiple conjugation quandle. We extend the notion of nn-parallel biquandle operations for any integer nn, an…

2017-02-05abs ↗pdf ↗

The paper bounds bandwidth and focal radius for manifolds with positive isotropic curvature.

problem Bounding bandwidth and focal radius for manifolds with positive isotropic curvature.
method Using spectral properties of a twisted de Rham-Hodge operator.
result Upper bounds on bandwidth and focal radius are derived for hypersurfaces in PIC manifolds.

The paper studies Jacobi fields and conjugate points in projective sprays.

problem Investigating Jacobi fields and conjugate points in projective sprays.
method Proved that conjugate points are preserved under projective changes and established conditions for the existence of conjugate points.
result Conditions for the existence of conjugate points in projectively deformed sprays.

Paper describes how to extend multiple conjugation quandles using maps.

problem Understanding affine extensions of multiple conjugation quandles.
method Introduces augmented MCQ Alexander pairs for affine extensions.
result Affine extensions of multiple conjugation quandles can be described by quadruples of maps.

Smooths metrics on manifolds with curvature bounds and injectivity radius constraints.

problem Smooth metrics on manifolds with curvature and injectivity constraints.
method Bi-Lipschitz smoothing with controlled smoothing and volume lower bounds.
result Proves existence of smooth metrics with curvature bounds and injectivity radius constraints.

For a surface group, a new bound is given for conjugator length function.

problem Finding an explicit bound for the conjugator length function of a surface group.
method Detailed analysis of conjugation reductions.
result An explicit bound n1CL(2n)n+8g1n-1 \leq \mathrm{CL}(2n) \leq n+8g-1 for the conjugator length function of a surface group.

The study examines Hopfian properties of conjugation quandles and their underlying groups.

problem Understanding the relationship between Hopfian properties of conjugation quandles and their underlying groups.
method Examined Hopfian and residual finiteness properties of conjugation quandles of specific groups.
result Conjugation quandles of Baumslag-Solitar groups are infinitely generated and not necessarily Hopfian.

A translation structure equips a Riemann surface with a singular flat metric. Not much is known about the shape of a random translation surface. We compute an upper bound on the expected value of the covering radius of a translation surface in any stratum H_1(kappa). The covering radius of a translation surface is the …

2018-09-27abs ↗pdf ↗

This paper considers metric balls B(p,R)B(p,R) in two dimensional Riemannian manifolds when RR is less than half the convexity radius. We prove that Area(B(p,R))8πR2Area(B(p,R)) \geq \frac{8}πR^2. This inequality has long been conjectured for RR less than half the injectivity radius. This result also yields the upper bound $μ_2(B(p,R)…

2017-01-23abs ↗pdf ↗