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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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16334965 · Oct 201919922001200920172026
48 results for injective words

The paper studies combinatorics of injective words in the context of Temperley-Lieb algebras.

problem Combinatorial properties of injective words in the context of Temperley-Lieb algebras.
method Investigation of a chain complex of modules over the Temperley-Lieb algebra, focusing on Euler characteristic, homology modules, and Jacobsthal numbers.
result The Euler characteristic of the complex is the n-th Fine number, and the top-dimensional homology module is decomposed in terms of standard Young tableaux.

This paper gives a proof that the fundamental group of a class of closed orientable 3-manifolds constructed from three injective handlebodies has a solvable word problem. This is done by giving an algorithm to decide if a closed curve in the manifold is null-homotopic. Non-Haken and non-Seifert fibered examples are con…

2006-01-30abs ↗pdf ↗

Study fixed point indices and words at infinity for graph selfmaps.

problem Estimate indices of fixed point classes for graph selfmaps.
method Extend attracting fixed words at infinity, use relative train track technique, algebraic approach.
result Upper bound for attracting fixed words of injective endomorphisms of free groups.

A longstanding question of Gromov asks whether every one-ended word-hyperbolic group contains a subgroup isomorphic to the fundamental group of a closed hyperbolic surface. An infinite family of word-hyperbolic groups can be obtained by taking doubles of free groups amalgamated along words that are not proper powers. W…

2009-10-25abs ↗pdf ↗

A {\em word labeled oriented graph} (WLOG) is an oriented graph G\cal G on vertices X={x1,,xk}X=\{ x_1,\ldots ,x_k\}, where each oriented edge is labeled by a word in X±1X^{\pm1}. WLOGs give rise to presentations which generalize Wirtinger presentations of knots. WLOG presentations, where the underlying graph is a tree are of …

2014-08-17abs ↗pdf ↗

If GG is a finite group, is a function f:GCf:G\to\mathbb C determined by its sums over all cosets of cyclic subgroups of GG? In other words, is the Radon transform on GG injective? This inverse problem is a discrete analogue of asking whether a function on a compact Lie group is determined by its integrals over all ge…

2014-11-14abs ↗pdf ↗

Lehmer's question is equivalent to one about generalized growth rates of Lefschetz numbers of iterated pseudo-Anosov surface homeomorphisms. One need consider only homeomorphisms that arise as monodromies of fibered knots in lens spaces L(n,1), n>0. Lehmer's question for Perron polynomials is equivalent to one about ge…

2005-09-03abs ↗pdf ↗

Injectivity of ReLU networks studied using statistical physics.

problem When can the input of a ReLU neural network be inferred from its output?
method Connection to spherical integral geometry and statistical physics.
result Replica symmetry-breaking theory and Gordon's min--max theorem provide insights into the injectivity threshold.

Let GG be a non-elementary word-hyperbolic group acting as a convergence group on a compact metrizable space ZZ so that there exists a continuous GG-equivariant map i:GZi:\partial G\to Z, which we call a \emph{Cannon-Thurston map}. We obtain two characterzations (a dynamical one and a geometric one) of conical limit p…

2014-01-12abs ↗pdf ↗

There is a well known injective homomorphism φ:BnAut(Fn)φ:{\mathcal {B}}_n \rightarrow {\rm Aut}(F_n) from the classical braid group Bn{\mathcal {B}}_n into the automorphism group of the free group FnF_n, first described by Artin. This homomorphism induces an action of Bn{\mathcal {B}}_n on FnF_n that can be recovered by consid…

2014-11-23abs ↗pdf ↗

New algorithm improves interpretability in sequence classification.

problem Lack of human-independent interpretability metrics in sequence classification.
method Combines linear classifiers with background knowledge embeddings to create a new feature space.
result Preserves predictive power while delivering more interpretable models.

The Transformer architecture has become increasingly popular over the past two years, owing to its impressive performance on a number of natural language processing (NLP) tasks. However, all Transformer computations occur at the level of word representations and therefore, it may be argued that Transformer models do no…

2019-10-16abs ↗pdf ↗

Proposes a text perturbation method using a Mahalanobis metric to balance privacy and utility.

problem Low utility of text analysis when using spherical noise for privacy-preserving text embedding.
method Regularized Mahalanobis metric to add elliptical noise, accounting for embedding space density.
result Improves privacy statistics while maintaining utility, outperforming Laplace mechanism.

In this paper we introduce a homotopy theoretic technique for proving that the KK-theoretic assembly map is an equivalence. It is an extension of the methods used to prove split injectivity of the assembly and applies to any geometrically finite group. Our result is that there are two requirements which need to hold. …

2013-05-15abs ↗pdf ↗

We present trellis networks, a new architecture for sequence modeling. On the one hand, a trellis network is a temporal convolutional network with special structure, characterized by weight tying across depth and direct injection of the input into deep layers. On the other hand, we show that truncated recurrent network…

2018-10-15abs ↗pdf ↗

Injectivity of ReLU networks is characterized for generative models and inverse problems.

problem Injectivity in ReLU networks for generative models and inverse problems.
method Layerwise analysis, worst-case Lipschitz constants, differential topology, random projections.
result Global injectivity of ReLU networks requires expansivity between 3.4 and 10.5 for Gaussian matrices.

The paper analyzes optimal dividend and capital injection strategies under time-inconsistent preferences.

problem Optimal dividend and capital injection strategies under time-inconsistent preferences.
method Diffusion risk model with general discount functions, weak equilibrium definition, HJB equation system.
result Explicit solutions and threshold types of optimal strategies derived under different discount functions.

A quasi-geodesic is Morse if and only if it is strongly contracting in injective spaces.

problem Characterizing Morse quasi-geodesics in injective spaces.
method Proving equivalence between Morse and strongly contracting quasi-geodesics.
result Injective metric spaces have the Morse local-to-global property and acylindrically hyperbolic groups with Morse elements.

This paper connects noise injection to Bayesian inference for neural networks, improving model uncertainty.

problem Improving the reliability and confidence of neural network predictions through uncertainty quantification.
method Introducing noise into neural network parameters during training and inference to estimate prediction uncertainty.
result The MCNI method outperforms baseline models in regression and classification tasks.

Lecture notes on group actions on injective spaces and Helly graphs.

problem Understanding group actions on specific metric spaces.
method Review of injective metric spaces and Helly graphs, elementary properties, constructions, and exercises.
result Presentation of various constructions of injective metric spaces and Helly graphs with interesting group actions.

Reservoir subspace injection improves online ICA by preserving injected features.

problem Discarding injected features in top-nn whitening can degrade performance.
method Formalized reservoir subspace injection (RSI) and developed diagnostics (IER, SSO, ρ_x) to identify and mitigate the failure mode.
result RSI controller preserves passthrough retention, improving performance by up to 2.2 dB.

Injective and surjective neural operators for function spaces.

problem Tackles injective and surjective neural operators in function spaces.
method Combines prior work in ReLU and operator learning, uses Fredholm theory and Leray-Schauder degree theory.
result Injective and surjective neural operators are universal approximators and maintain their properties in finite-rank implementations.

Smooths metrics on manifolds with curvature bounds and injectivity radius constraints.

problem Smooth metrics on manifolds with curvature and injectivity constraints.
method Bi-Lipschitz smoothing with controlled smoothing and volume lower bounds.
result Proves existence of smooth metrics with curvature bounds and injectivity radius constraints.

Nonuniform tubular neighborhoods of curves in Euclidean n-space are studied by using weighted distance functions and generalizing the normal exponential map. Different notions of injectivity radii are introduced to investigate singular but injective exponential maps. A generalization of the thickness formula is obtaine…

2007-05-16abs ↗pdf ↗

In this paper, we obtain two-sided bounds for the volumes of the Aloff-Wallach spaces W(p,q),W(p,q), compute maximal and minimal sectional curvature for the spaces W(n,n+1),W(n,n+1), and use this information to estimate the injectivity radii: We derive an upper bound for the injectivity radii of W(p,q)W(p,q) and a lower bound for the …

2005-11-24abs ↗pdf ↗

Injectivity of geodesic ray transform on specific Finsler manifolds proven.

problem Injectivity of geodesic ray transform on spherically symmetric reversible Finsler manifolds.
method Reduction to invertibility of generalized Abel transforms using angular Fourier series and Taylor expansions of geodesics.
result Injectivity of geodesic ray transform proven on specified Finsler manifolds.

Separable Non-negative Matrix Factorization (SNMF) is an important method for topic modeling, where "separable" assumes every topic contains at least one anchor word, defined as a word that has non-zero probability only on that topic. SNMF focuses on the word co-occurrence patterns to reveal topics by two steps: anchor…

2019-05-10abs ↗pdf ↗

Optimal control problem for firm cash flow with dividend and capital injection strategies.

problem Maximizing dividends while managing capital injections in a firm's cash flow.
method Proved two optimal strategies: mean-reverting dividends with capital injections or no injections until ruin.
result Optimal strategies are dichotomous: either mean-reverting dividends with injections or no injections.

A labeled oriented tree is called injective if each generator occurs at most once as an edge label. We show that injective labeled oriented trees are aspherical. The proof relies on a new relative asphericity test based on a lemma of Stallings.

2012-12-10abs ↗pdf ↗

Most existing word embedding approaches do not distinguish the same words in different contexts, therefore ignoring their contextual meanings. As a result, the learned embeddings of these words are usually a mixture of multiple meanings. In this paper, we acknowledge multiple identities of the same word in different co…

2016-11-29abs ↗pdf ↗

The exponential map fails to be injective near critical points in sub-Riemannian geometry.

problem Injectivity failure of the exponential map at critical points in sub-Riemannian geometry.
method Analysis of the Hilbert invariant integral of the variational problem associated with the sub-Riemannian structure.
result Characterization of conjugate points in terms of metric structure.