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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.

169,051 papers · 148 categories

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48 results for rectangular representations

Researchers extend knot theory formulas to non-rectangular cases.

problem Applying universal-matrix precursor formulas to non-rectangular knot representations.
method Reformulated previously known formulas for simplest non-rectangular representations [r,1].
result Demonstrated drastic simplification of formulas after reformulation.

New formula simplifies evolution of twist knots and calculates Racah matrices for rectangular representations.

problem Simplifying evolution of twist knots and calculating Racah matrices for rectangular representations.
method Developed a universal formula for triangular evolution matrix B{\cal B} applicable to rectangular representations R=[rs]R=[r^s]. Used skew characters and Macdonald polynomials.
result Explicit knowledge of twist-family evolution leads to a nearly explicit answer for Racah matrix Sˉ\bar S in arbitrary rectangular representation RR.

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 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 ↗

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 ↗

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.

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 ↗

Differential expansion (DE) for a Wilson loop average in representation RR is built to respect degenerations of representations for small groups. At the same time it behaves nicely under some changes of the loop, e.g. of some knots in the case of 3d3d Chern-Simons theory. Especially simple is the relation between the …

2016-05-31abs ↗pdf ↗

Many knots and links in S^3 can be drawn as gluing of three manifolds with one or more four-punctured S^2 boundaries. We call these knot diagrams as double fat graphs whose invariants involve only the knowledge of the fusion and the braiding matrices of four-strand braids. Incorporating the properties of four-point con…

2015-04-01abs ↗pdf ↗

Inspired by the paper on quantum knots and knot mosaics [23] and grid diagrams (or arc presentations), used extensively in the computations of Heegaard-Floer knot homology [2,3,7,24], we construct the more concise representation of knot mosaics and grid diagrams via mirror-curves. Tame knot theory is equivalent to knot…

2011-06-19abs ↗pdf ↗

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.

Conjectures closed-form expressions and cyclotomic expansions for knot invariants.

problem Calculating HOMFLY-PT invariants of knots colored by rectangular diagrams.
method Interpolation Macdonald polynomials and cyclotomic expansions.
result Conjectured closed-form expressions and cyclotomic expansions for knot invariants.

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 ↗

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}).

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 ↗

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.

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 ↗

As a new step in the study of rectangularly-colored knot polynomials, we reformulate the prescription of arXiv:1606.06015 for twist knots in the double-column representations R=[rr]R=[rr] in terms of skew Schur polynomials. These, however, are mysteriously shifted from the standard topological locus, what makes further gen…

2016-10-15abs ↗pdf ↗

Rectangular Bounding Process (RBP) improves partitioning efficiency in multi-dimensional spaces.

problem Creating many unnecessary divisions in sparse regions when describing dense regions.
method Introduces Rectangular Bounding Process (RBP) to efficiently partition multi-dimensional spaces using a bounding strategy.
result The RBP is self-consistent and can be extended to infinite space, offering rich yet parsimonious expressiveness.

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.

New kernel models multi-output Gaussian processes accurately.

problem Challenges in modelling cross-covariances for multiple-output Gaussian processes.
method Replaced Gaussian components with block components of finite bandwidth in spectral mixture kernel.
result First multi-output generalization of spectral mixture kernel that can approximate any stationary multi-output kernel to arbitrary precision.

We study the structural properties of colored Kauffman homologies of knots. Quadruple-gradings play an essential role in revealing the differential structure of colored Kauffman homology. Using the differential structure, the Kauffman homologies carrying the symmetric tensor products of the vector representation for th…

2013-10-08abs ↗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.

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 ↗

Reconstruction of density functions and their characteristic functions by radial basis functions with scattered data points is a popular topic in the theory of pricing of basket options. Such functions are usually entire or admit an analytic extension into an appropriate tube and "bell-shaped" with rapidly decaying tai…

2014-04-21abs ↗pdf ↗

Braid monodromy is an important tool for computing invariants of curves and surfaces. In this paper, the \emph{rectangular braid diagram (RBD)} method is proposed to compute the braid monodromy of a completely reducible nn-gonal curve, i.e. the curves in the form (yy1(x))...(yyn(x))=0(y-y_1(x))...(y-y_n(x))=0 where nZ+n\in \mathbb{Z}^{+}

2016-11-01abs ↗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 ↗