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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.

168,742 papers · 148 categories

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48 results for 1-3 type tetrahedra

Study rigidity and volume optimization of hyperbolic polyhedra.

problem Rigidity and volume optimization of hyperbolic polyhedra.
method Analyzing decorated 1-3 type hyperbolic polyhedra and their metrics.
result Decorated 1-3 type hyperbolic polyhedra are rigid up to isometry and change of decorations.

We give a unified description of tetrahedra with lightlike faces in 3d anti-de Sitter, de Sitter and Minkowski spaces and of their duals in 3d anti-de Sitter, hyperbolic and half-pipe spaces. We show that both types of tetrahedra are determined by a generalized cross-ratio with values in a commutative 2d real algebra t…

2019-09-03abs ↗pdf ↗

The paper connects quantum 6j6j-symbols to tetrahedra volumes via discrete Fourier transforms.

problem Understanding the asymptotic behavior of quantum 6j6j-symbols and their relation to 3-manifold invariants.
method Proposing and proving a conjecture linking discrete Fourier transforms of quantum 6j6j-symbols to the volumes of deeply truncated tetrahedra.
result Supporting evidence for the conjecture in specific cases, with numerical calculations for larger dihedral angles.

The paper defines new homotopy relations on knot projections and classifies certain knot types.

problem Defining and classifying knot homotopy relations.
method Introducing cross chord numbers and using them to define strong and weak (1, 3) homotopies.
result Complete classification of knot projections with trivializing number two.

We compute for all orientable irreducible geometric 3-manifolds certain complexity functions that approximate from above Matveev's natural complexity, known to be equal to the minimal number of tetrahedra in a triangulation. We can show that the upper bounds on Matveev's complexity implied by our computations are sharp…

2003-03-20abs ↗pdf ↗

In this study, we define some new types of non-null ruled surfaces called slant ruled surfaces in the Minkowski 3-space E_1^3. We introduce some characterizations for a non-null ruled surface to be a slant ruled surface in E_1^3. Moreover, we obtain some corollaries which give the relationships between a non-null slant…

2016-04-12abs ↗pdf ↗

The paper proves a Minkowski-like theorem for tetrahedra in dS3 and AdS3.

problem Formulating and proving a constant-curvature, holonomy-valued Lorentzian analogue of Minkowski theorem for tetrahedra.
method Formulated and proved a Lorentzian analogue of Minkowski theorem for tetrahedra in dS3 and AdS3.
result A unique strictly convex tetrahedron can be reconstructed from four non-trivial based SO+(1,2) holonomies.

Randomly glued tetrahedra form connected 3-manifolds with a single boundary.

problem Understanding the properties of random three-manifolds formed by truncated tetrahedra.
method Asymptotic analysis of random glued manifolds, proving laws of large numbers, and bounding various topological and geometric properties.
result The random manifolds are connected, have a single boundary component, and admit a unique hyperbolic metric with a uniform spectral gap.

Motivated by the Turaev-Viro invariant of 3-manifolds, we construct a formal topological invariant of closed, oriented 3-manifolds involving spherical tetrahedra as an application of the asymptotic formula of 6j symbols for the Quantum Enveloping Algebra of sl(2). This invariant can be considered as a spherical version…

2004-06-11abs ↗pdf ↗

Quaternionic curves with specific torsion properties don't exist.

problem Existence of quaternionic Bertrand curves with non-zero torsion and bitorsion.
method Definition of quaternionic (1,3)-Bertrand curves using Type 2-Quaternionic Frame and Matsuda-Yorozu method.
result No quaternionic Bertrand curves with non-zero torsion and bitorsion exist.

We classify the orientable finite-volume hyperbolic 3-manifolds having non-empty compact totally geodesic boundary and admitting an ideal triangulation with at most four tetrahedra. We also compute the volume of all such manifolds, we describe their canonical Kojima decomposition, and we discuss manifolds having cusps.…

2002-11-27abs ↗pdf ↗

Researchers found the minimum number of tetrahedra needed to triangulate elliptic and sol 3-manifolds.

problem Finding the minimum number of tetrahedra in triangulations of 3-manifolds.
method Computed the triangulation complexity of all elliptic and sol 3-manifolds, within a bounded error.
result Computed the triangulation complexity of all elliptic and sol 3-manifolds.

Researchers found the Wigner derivative and its inverse are equal for spherical tetrahedra.

problem Computing the relationship between dihedral angles and edge lengths in tetrahedra.
method Computed the Wigner derivative and its inverse for spherical tetrahedra.
result The Wigner derivative and its inverse are equal for spherical tetrahedra.

In the paper we define a "volume" for simplicial complexes of flag tetrahedra. This generalizes and unifies the classical volume of hyperbolic manifolds and the volume of CR tetrahedra complexes. We describe when this volume belongs to the Bloch group. In doing so, we recover and generalize results of Neumann-Zagier, N…

2011-01-14abs ↗pdf ↗

Hyperideal tetrahedra are the fundamental building blocks of hyperbolic 3-manifolds with geodesic boundary. The study of their geometric properties (in particular, of their volume) has applications also in other areas of low-dimensional topology, like the computation of quantum invariants of 3-manifolds and the use of …

2018-01-16abs ↗pdf ↗

We give a rigorous geometric proof of the Murakami-Yano formula for the volume of a hyperbolic tetrahedron. In doing so, we are led to consider generalized hyperbolic tetrahedra, which are allowed to be non-convex, and have vertices `beyond infinity'; and we uncover a group, which we call 22.5K, of 23040 scissors-class…

2003-09-10abs ↗pdf ↗

We analyze the dynamical properties of a tetrahedron transformation on the space of non-degenerate tetrahedra which can be identified with the non-compact globally symmetric 88-dimensional space $\mbox{Sl}(3,\mathbb{R}) / \mbox{So}(3,\mathbb{R})$. We establish the existence of a local attractor which coincides with th…

2017-08-28abs ↗pdf ↗

We describe the deformation space of a solid torus with boundary modelled on convex ideal hyperbolic polyhedra. This deformation space is given by natural Gauss--Bonnet type inequalities on the dihedral angles. The result extends to solid tori with an arbitrary conical singularity along the core. Our method is to decom…

2009-11-16abs ↗pdf ↗

Study laws of cosines and sines for hyperbolic shapes with ideal vertices.

problem Formulating trigonometric laws for shapes with ideal vertices in hyperbolic geometry.
method Using hyperboloid model and Lorentzian geometry, establishing laws for quadrilaterals, pentagons, and partially truncated tetrahedra.
result Transversal lengths of partially truncated tetrahedra depend only on internal edge lengths at ideal vertices.

A generalized hyperbolic tetrahedra is a polyhedron (possibly non-compact) with finite volume in hyperbolic space, obtained from a tetrahedron by the polar truncation at the vertices lying outside the space. In this paper it is proved that a volume formula for ordinary hyperbolic tetrahedra devised by J. Murakami and M…

2003-09-12abs ↗pdf ↗

Study geometry of tetrahedra in complex hyperbolic space and Hilbert spaces.

problem Understanding geometric relationships between complex hyperbolic spaces and Hilbert spaces.
method Use a complex analog of the cosine of a vertex angle as a novel technical tool.
result Describe possible triangular faces of tetrahedra in hyperbolic space and three-dimensional subspaces in Hilbert spaces with Pick kernels.

Starting with an ideal triangulation of the interior of a compact 3-manifold M with boundary, no component of which is a 2-sphere, we provide a construction, called an inflation of the ideal triangulation, to obtain a strongly related triangulations of M itself. Besides a step-by-step algorithm for such a construction,…

2013-02-27abs ↗pdf ↗

In this paper we provide the first examples of non-flat soap films proven to span tetrahedra. These are members of a continuous two parameter family of soap films with tetrahedral boundaries. Of particular interest is a two parameter subfamily where each spanning soap film has the property that two minimal surfaces mee…

2008-09-02abs ↗pdf ↗

Characterizes billiard and quasigeodesic flows in polyhedral convex bodies.

problem Characterizing billiard and quasigeodesic flows in polyhedral convex bodies.
method Alexandrov geometry methods.
result Optimal regularity result for convex bodies: billiard dynamics is continuous if boundary is of class C2,1\mathcal{C}^{2,1}.

From its creation in 1989 through subsequent extensions, the widely-used "SnapPea census" now aims to represent all cusped finite-volume hyperbolic 3-manifolds that can be obtained from <= 8 ideal tetrahedra. Its construction, however, has relied on inexact computations and some unproven (though reasonable) assumptions…

2014-05-12abs ↗pdf ↗

New algorithm tackles non-stationary RL with near-optimal regret bounds.

problem Model-free reinforcement learning in non-stationary Markov decision processes.
method Proposed RestartQ-UCB algorithm with Freedman-type bonus terms.
result Achieves near-optimal dynamic regret bound in non-stationary RL.

The paper classifies surfaces with constant curvature in 3D De Sitter and anti De Sitter spaces.

problem Classifying surfaces with constant curvature in 3D De Sitter and anti De Sitter spaces.
method Analyzing conditions equivalent to constant principal curvature, mean curvature, and second mean curvature.
result Surfaces of L1L_1-2-type in De Sitter and anti De Sitter spaces are either standard products, scrolls, or have non-constant curvature properties.

Given a combinatorial description CC of a polyhedron having EE edges, the space of dihedral angles of all compact hyperbolic polyhedra that realize CC is generally not a convex subset of RE\mathbb{R}^E \cite{DIAZ}. If CC has five or more faces, Andreev's Theorem states that the corresponding space of dihedral angle…

2006-01-07abs ↗pdf ↗