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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.

169,291 papers · 148 categories

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2.6%5.3%7.9%10.5% · Jan 199719922001200920182026
48 results for null strings

Study properties of null string congruences in complex and real pseudo-Riemannian spaces.

problem Analyze properties of null string congruences in 4D spaces.
method Investigate the geometry of null strings and their congruences in complex and real pseudo-Riemannian spaces.
result Relations between null string congruences, Petrov-Penrose types, and Ricci tensor algebraic types are established.

We extend knot Floer homology to string links in D^{2} \times I and to d-based links in arbitrary three manifolds, without any hypothesis on the null-homology of the components. As for knot Floer homology we obtain a description of the Euler characteristic of the resulting homology groups (in D^{2} \times I) in terms o…

2006-07-10abs ↗pdf ↗

We determine the geometry of supersymmetric heterotic string backgrounds for which all parallel spinors with respect to the connection ^\hat\nabla with torsion HH, the NS\otimesNS three-form field strength, are Killing. We find that there are two classes of such backgrounds, the null and the timelike. The Killing s…

2005-10-20abs ↗pdf ↗

Derives path integrals for perturbative strings on various backgrounds.

problem Calculating path integrals for strings on curved backgrounds.
method Derives path integrals from string geometry theory by considering fluctuations around string backgrounds.
result Derives path integrals of all order perturbative strings on various backgrounds.

Derives path-integrals for superstrings on curved backgrounds using string geometry theory.

problem Calculating path-integrals for superstrings on curved backgrounds.
method Derives path-integrals from string geometry theory by considering fluctuations around string backgrounds.
result Derives path-integrals for perturbative superstrings on all string backgrounds.

Chiral string integrands simplify to ambitwistor string integrands in the tensionless limit.

problem Understanding the relationship between chiral and ambitwistor string integrands.
method Analyzing the tensionless limit of chiral superstring integrands.
result Chiral superstring integrands reduce to ambitwistor string integrands in the tensionless limit.

A virtual string can be defined as an equivalence class of planar diagrams under certain kinds of diagrammatic moves. Virtual strings are related to virtual knots in that a simple operation on a virtual knot diagram produces a diagram for a virtual string. In this paper we consider three operations on a virtual string …

2008-08-04abs ↗pdf ↗

A virtual string is a scheme of self-intersections of a closed curve on a surface. We study algebraic invariants of strings as well as two equivalence relations on the set of strings: homotopy and cobordism. We show that the homotopy invariants of strings form an infinite dimensional Lie group. We also discuss connecti…

2003-11-12abs ↗pdf ↗

Research extends Cahn's results on virtual strings to connected non-parallel strings.

problem Understanding the homotopy of virtual strings and their minimal representatives.
method Generalization of Cahn's results using stabilizations, destabilizations, and homotopies.
result Kadokami's statement about virtual strings holds for connected non-parallel strings but not for all strings.

Extended Alexander groups are used to define an invariant for open virtual strings. Examples of non-commuting open strings and a ribbon-concordance obstruction are given. An example is given of a slice virtual open string that is not ribbon. Definitions are extended to open n-strings.

2004-09-10abs ↗pdf ↗

We present a finite-dimensional and smooth formulation of string structures on spin bundles. It uses trivializations of the Chern-Simons 2-gerbe associated to this bundle. Our formulation is particularly suitable to deal with string connections: it enables us to prove that every string structure admits a string connect…

2009-05-30abs ↗pdf ↗

Study topological G₂ and Spin(7) strings at 1-loop using double complexes.

problem Calculate topological string partition functions at 1-loop.
method Define double complexes for supersymmetric backgrounds using generalised geometry, compute partition functions as alternating products of determinants of Laplacians.
result Reproduce known results for G₂ string and predict for Spin(7) string.

In this note we revisit the subject of anomaly cancelation in string theory and M-theory on manifolds with String structure and give three observations. First, that on String manifolds there is no E8 x E8 global anomaly in heterotic string theory. Second, that the description of the anomaly in the phase of the M-theory…

2008-07-30abs ↗pdf ↗

A virtual string is a scheme of self-intersections of a closed curve on a surface. We introduce virtual strings and study their geometric properties and homotopy invariants. We also discuss connections between virtual strings, Gauss words, and virtual knots.

2003-10-15abs ↗pdf ↗

End-to-end solution for recognizing handwritten numerals, avoiding traditional preprocessing steps.

problem Handwritten numeral string recognition with traditional preprocessing steps.
method YoLo-based model for automatic detection and recognition, avoiding heuristic-based preprocessing and segmentation.
result Proposed method reduces complexity and is a feasible end-to-end solution for numeral string recognition.

We derive a recursion relation for hyperbolic string vertices and apply it to string field theory.

problem Deriving a recursion relation for hyperbolic string vertices and its implications for string field theory.
method Using systolic volumes and a modified Mirzakhani's recursion, we construct a higher-order vertex determination for hyperbolic string field theory.
result The higher order vertices in hyperbolic string field theory are determined by the cubic vertex iteratively for any background.

In this study, we define a family of null curves in Minkowski 3-space and called null similar curves. We obtain some properties of these special curves. We show that two null curves are null similar curves if and only if these curves form a null Bertrand pair. Moreover, we obtain that the family of null geodesics and n…

2012-05-10abs ↗pdf ↗

The multi dimensional string objects are introduced as a new alternative for an application of string models for time series forecasting in trading on financial markets. The objects are represented by open string with 2-endpoints and D2-brane, which are continuous enhancement of 1-endpoint open string model. We show ho…

2016-07-18abs ↗pdf ↗

New string kernels discover global properties through random feature maps, avoiding quadratic complexity.

problem Existing string kernels struggle with capturing long patterns, maintaining positive definiteness, and handling large datasets efficiently.
method Proposes a new class of global string kernels using random feature maps to discover global properties through global alignments, ensuring positive definiteness and linear computational cost.
result Random String Embeddings (RSE) achieve better or comparable accuracy to state-of-the-art methods, especially for longer strings.

STRING improves 2D and 3D position encodings for better performance.

problem Efficient and accurate position encoding for 2D and 3D applications.
method STRING extends Rotary Position Encodings with a unifying theoretical framework, maintaining translation invariance and low computational cost.
result STRING shows substantial gains in open-vocabulary object detection and robotics.

Space-efficient feature maps improve string alignment kernel scalability.

problem String alignment kernels scale poorly with quadratic complexity, limiting large-scale applications.
method Presented SFMEDM, a space-efficient feature map for edit distance with moves using metric embedding and random Fourier features.
result Demonstrated superior performance of SFMEDM in prediction accuracy, scalability, and computation efficiency.

In this paper we use 3-manifold techniques to illuminate the structure of the string link monoid. In particular, we give a prime decomposition theorem for string links on two components as well as give necessary conditions for string links to commute under the stacking operation.

2013-08-07abs ↗pdf ↗

Numbers and numerical vectors account for a large portion of data. However, recently the amount of string data generated has increased dramatically. Consequently, classifying string data is a common problem in many fields. The most widely used approach to this problem is to convert strings into numerical vectors using …

2014-06-03abs ↗pdf ↗

The Tong-Yang-Ma representations are extended to string links and welded string links.

problem Extending Tong-Yang-Ma representations to string links and welded string links.
method Using the method of Silver and Williams, the authors extend the Tong-Yang-Ma representations.
result The kernels of the extended representations can be described using linking numbers.

Analyzes string topology operations using Chen's integrals and homotopy transfer.

problem Relating string topology to perturbative Chern-Simons theory.
method Develops integrals over configuration spaces and applies homotopy transfer.
result Intertwines involutive Lie bialgebra structures on homology.