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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.

168,657 papers · 148 categories

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5101419 · May 202119922001200920172026
48 results for Rectangular lattices

We find coordinates, the metric tensor, the inverse metric tensor and the Laplace-Beltrami operator for the orbit space of Hamiltonian SU(2) gauge theory on a finite, rectangular lattice. This is done using a complete axial gauge fixing. The Gribov problem can be completely solved, with no remaining gauge ambiguities.

2012-03-22abs ↗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 ↗

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 ↗

New system studies trapped light paths in Euclidean space.

problem Trapping of light paths in Euclidean space with negative refractive index.
method Introduces wind-tree tiling billiards system to study trajectories of rays in Euclidean space with rectangular obstacles.
result Almost every configuration of the system traps trajectories with initial vertical direction in an infinite strip.

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 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.

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.

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.

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 ↗

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 ↗

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 ↗

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 ↗

Rectangular diagrams of links are link diagrams in the plane R2{\mathbb R}^2 such that they are composed of vertical line segments and horizontal line segments and vertical segments go over horizontal segments at all crossings. P. R. Cromwell and I. A. Dynnikov showed that rectangular diagrams of links are useful for d…

2014-05-27abs ↗pdf ↗

We study immersed tori in 33-space minimizing the Willmore energy in their respective conformal class. Within the rectangular conformal classes   (0,b)  \;(0,b)\; with   b1  \;b \sim 1\; the homogenous tori   fb  \;f^b\; are known to be the unique constrained Willmore minimizers (up to invariance). In this paper we generalize this r…

2017-10-02abs ↗pdf ↗

New algorithm for signal estimation in noisy matrix models.

problem Signal estimation in rectangular spiked matrix models with rotationally invariant noise.
method Orthogonal Approximate Message Passing (OAMP) algorithm for signal estimation.
result Optimal OAMP algorithm minimizes mean-squared error and achieves Bayes-optimal performance.

Study non-rectangular robust MDPs for average-reward, finding optimal policies and transient values.

problem Non-rectangular robust Markov decision processes under average-reward criterion.
method Proves history-dependent policies are robust-optimal, introduces transient-value framework, constructs epoch-based policy.
result Existence and properties of robust optimal policies, transient value bounds.