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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 rectangular torus

Square Clifford torus uniquely determined by isoperimetric ratio, rectangular torus not.

problem Uniqueness of 3D shape of rectangular Clifford torus based on isoperimetric ratio.
method Closed-form formulas for isoperimetric ratio of stereographic projection, strict monotonicity.
result Isoperimetric ratio does not uniquely determine rectangular Clifford torus shape.

Minimal tori that are linearly full in the 3-sphere possess a natural invariant g called their spectral genus, which was introduced by Hitchin. We show that for each g>0, there are countably many real g-dimensional families of minimally immersed tori with spectral genus g (two of these dimensions are just reparametrisa…

2004-07-16abs ↗pdf ↗

We show that the homogeneous and the 2-lobe Delaunay tori in the 3-sphere provide the only isothermic constrained Willmore tori in 3-space with Willmore energy below 8π. In particular, every constrained Willmore torus with Willmore energy below 8π and non-rectangular conformal class is non-degenerated.

2019-03-28abs ↗pdf ↗

Formula found for probability of random triangles on flat tori being homotopically trivial.

problem Calculating the probability of random triangles on flat tori being homotopically trivial.
method Reduced problem to new invariant of measurable sets in the plane unchanged by area-preserving affine transformations.
result Probability is minimized on rectangular tori and maximized on regular hexagonal tori.

Study minimal surfaces in 4D, find specific tori with total curvature -8π.

problem Find complete proper non-holomorphic minimal tori in R^4 with total curvature -8π.
method Use tools like Gauss maps and link/braid/writhe at infinity. Translate problem into a system of equations involving Weierstrass function. Explicitly solve for rectangular and square tori.
result Explicit solutions for minimal tori in R^4, including generalization of Chen-Gackstetter torus in R^3.

If a rectangular diagram represents the trivial knot, then it can be deformed into the rectangular diagram with only two vertical edges by a finite sequence of merge operations and exchange operations, without increasing the number of vertical edges, which was shown by I. A. Dynnikov. We show in this paper that we need…

2013-03-27abs ↗pdf ↗

In this paper Legendrian graphs in (R3,ξst)(\mathbb{R}^3,ξ_{\mathrm{st}}) are considered modulo Legendrian isotopy and edge contraction. To a Legendrian graph we associate a (generalized) rectangular diagram --- a purely combinatorial object. Moves of rectangular diagrams are introduced so that equivalence classes of Legendr…

2014-12-06abs ↗pdf ↗

Paper studies S-rectangular DR-RL models for robust reinforcement learning with near-optimal sample complexity.

problem Addressing distributional discrepancies in reinforcement learning environments.
method Empirical value iteration algorithm for divergence-based S-rectangular DR-RL models.
result Near-optimal sample complexity bound of O(SA(1γ)4ε2)O(|\mathcal{S}||\mathcal{A}|(1-γ)^{-4}\varepsilon^{-2}).

We establish scale-invariant Strichartz estimates for the Schrödinger flow on any compact Lie group equipped with canonical rational metrics. In particular, full Strichartz estimates without loss for some non-rectangular tori are given. The highlights of this paper include estimates for some Weyl type sums defined on r…

2017-03-22abs ↗pdf ↗

We introduce a simple combinatorial way, which we call a rectangular diagram of a surface, to represent a surface in the three-sphere. It has a particularly nice relation to the standard contact structure on S3\mathbb S^3 and to rectangular diagrams of links. By using rectangular diagrams of surfaces we are going, in p…

2016-06-10abs ↗pdf ↗

Study reveals 1/f1/f noise in signals made from nonoverlapping rectangular pulses.

problem Analyzing 1/f1/f noise in signals composed of nonoverlapping pulses.
method Derived a general formula for power spectral density, analyzed rectangular pulse case.
result Observed pure 1/f1/f noise until very low frequencies with long pulse durations.

We claim that the recently discovered universal-matrix precursor for the FF functions, which define the differential expansion of colored polynomials for twist and double braid knots, can be extended from rectangular to non-rectangular representations. This case is far more interesting, because it involves multiplicit…

2019-03-01abs ↗pdf ↗

A correspondence is studied by H. Matsuda between front projections of Legendrian links in the standard contact structure for 3-space and rectangular diagrams. In this paper, we introduce braided rectangular diagrams, and study a relationship with Legendrian links in the standard contact structure for 3-space. We show …

2007-08-17abs ↗pdf ↗

New framework for higher-order singular-value derivatives of rectangular matrices.

problem Challenging to derive higher-order Fréchet derivatives of singular values in real rectangular matrices.
method Using Kato's analytic perturbation theory for self-adjoint operators and embedding rectangular matrices into block self-adjoint operators.
result Closed-form expressions for the nn-th order spectral variations of singular values.

We introduce a new braid-theoretic framework with which to understand the Legendrian and transversal classification of knots, namely a Legendrian Markov Theorem without Stabilization which induces an associated transversal Markov Theorem without Stabilization. We establish the existence of a nontrivial knot-type specif…

2008-01-22abs ↗pdf ↗

The moduli space of lattices of C\mathbb{C} is a Riemann surface of finite hyperbolic area with the square lattice as an origin. We select a lattice from the induced uniform distribution and calculate the statistics of the Teichmüller distance to the origin. This in turn identifies distribution of the distance in Teic…

2018-07-29abs ↗pdf ↗

Paper studies robust MDPs, improving sample complexity and asymptotic performance.

problem Optimal robust policy and value function in robust MDPs with generative models.
method Improves prior results on non-asymptotic and asymptotic performances of robust MDPs, considering various uncertainty sets.
result Improved sample complexity and asymptotic normality of optimal robust value function.

Factorization of the differential expansion coefficients for HOMFLY-PT polynomials of double braids, discovered in arXiv:1606.06015 in the case of rectangular representations RR, is extended to the first non-rectangular representations R=[2,1]R=[2,1] and R=[3,1]R=[3,1]. This increases chances that such factorization will take p…

2016-12-01abs ↗pdf ↗

We elaborate on the recent observation that evolution for twist knots simplifies when described in terms of triangular evolution matrix B{\cal B}, not just its eigenvalues ΛΛ, and provide a universal formula for B{\cal B}, applicable to arbitrary rectangular representation R=[rs]R=[r^s]. This expression is in terms of s…

2019-02-11abs ↗pdf ↗

Optimal unimodal fitting for linear loss functions in a sequential, efficient manner.

problem Optimal unimodal transformation of univariate model scores under linear loss functions.
method Proposes a sequential approach to estimate the optimal rectangular fit for observed samples with each new sample.
result Sequential approach achieves optimal efficiency with logarithmic time complexity per iteration.

Stochastic partition models divide a multi-dimensional space into a number of rectangular regions, such that the data within each region exhibit certain types of homogeneity. Due to the nature of their partition strategy, existing partition models may create many unnecessary divisions in sparse regions when trying to d…

2019-03-10abs ↗pdf ↗

We conjecture the existence of four independent gradings in the colored HOMFLY homology. We describe these gradings explicitly for the rectangular colored homology of torus knots and make qualitative predictions of various interesting structures and symmetries in the colored homology of general knots. We also give a si…

2013-04-11abs ↗pdf ↗

Simple rectilinear polygons (i.e. rectilinear polygons without holes or cutpoints) can be regarded as finite rectangular cell complexes coordinatized by two finite dendrons. The intrinsic l1l_1-metric is thus inherited from the product of the two finite dendrons via an isometric embedding. The rectangular cell complexe…

2010-05-11abs ↗pdf ↗

The paper finds rotationally symmetric critical metrics for Laplace eigenvalues on tori.

problem Maximizing the first normalized Laplace-Beltrami eigenvalue on tori.
method Constructing equivariant harmonic maps to spheres and analyzing their properties.
result Rotationally symmetric critical metrics for the first eigenvalue are found and characterized.

We rewrite the recently proposed differential expansion formula for HOMFLY polynomials of the knot 414_1 in arbitrary rectangular representation R=[rs]R=[r^s] as a sum over all Young sub-diagrams λλ of RR with extraordinary simple coefficients Dλtr(r)Dλ(s)D_{λ^{tr}}(r)\cdot D_λ(s) in front of the ZZ-factors. Somewhat miraculously…

2016-09-01abs ↗pdf ↗

For every   b>1  \;b>1\; fixed, we explicitly construct 11-dimensional families of embedded constrained Willmore tori parametrized by their conformal class   (a,b)\;(a,b)\; with   ab0+  \; a \sim_b 0^+\; deforming the homogenous torus \;fbf^b of conformal class \;(0,b).(0,b). The variational vector field at fbf^b is hereby given by a non…

2019-02-25abs ↗pdf ↗

We prove existence results that give information about the space of minimal immersions of 2-tori into S3 S ^ 3 . More specifically, we show that \begin{enumerate} \item For every positive integer n n , there are countably many real nn -dimensional families of minimally immersed 2-tori in S3 S ^ 3 . Every linearly ful…

2004-07-16abs ↗pdf ↗

Various semigroups of noninvertible supermatrices of the special (antitriangle) shape having nilpotent Berezinian which appear in supersymmetric theories are defined and investigated. A subset of them continuously represents left and right zero semigroups and rectangular bands. The ideal properties of higher order rect…

1996-09-19abs ↗pdf ↗