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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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76152228304 · Jun 202019922001200920172026
48 results for open vs closed

We present Vector-Space Markov Random Fields (VS-MRFs), a novel class of undirected graphical models where each variable can belong to an arbitrary vector space. VS-MRFs generalize a recent line of work on scalar-valued, uni-parameter exponential family and mixed graphical models, thereby greatly broadening the class o…

2015-05-19abs ↗pdf ↗

New framework detects near vs. far out-of-distribution samples for AI safety.

problem Binary OOD detection fails to distinguish between semantically close and distant unknown risks.
method Ternary classification based on Low-Entropy Semantic Manifolds and Semantic Surprise Vector.
result Framework achieves state-of-the-art performance on ternary OOD detection task.

The paper explores learning good policies from past data in large state spaces.

problem Learning good policies from historical data in large state spaces.
method Introduces expressivity assumptions and data coverage for function approximation and algorithmic design.
result A variety of algorithms and their guarantees are presented based on assumptions and desired complexity.

New bounds show transformers need longer training for length generalization.

problem Understanding when transformers can generalize to longer inputs.
method Analyzing different settings of transformers, providing quantitative bounds.
result Transformers need training data longer than previously thought for length generalization.

New method fuses optical and SAR data to fill LAI gaps during cloudy periods.

problem Cloudy periods mask key crop growth stages, leading to unreliable yield predictions.
method Multi-Output Gaussian Process (MOGP) regression for fusing Sentinel-1 RVI and Sentinel-2 LAI time series.
result MOGP provides improved LAI estimations even during cloudy periods, especially for long gaps.

This note introduces and studies an open set of PSL(2,C) characters of a nonabelian free group, on which the action of the outer automorphism group is properly discontinuous, and which is strictly larger than the set of discrete, faithful convex-cocompact (i.e. Schottky) characters. This implies, in particular, that th…

2009-06-18abs ↗pdf ↗

Given a smooth closed manifold M with a family {L_i} of closed submanifolds, we consider the free loop space LM and the spaces PM(L_i,L_j) of open strings (paths g:[0,1]->M with g(0) in L_i, and g(1) in L_j). We construct string topology operations resulting in an open-closed TQFT on the family (h_*(LM),h_*(PM(L_i,L_j)…

2006-06-20abs ↗pdf ↗

This paper studies optimal approximation factors in misspecified off-policy RL, identifying key factors under various settings.

problem Understanding optimal approximation factors in misspecified off-policy value function estimation.
method Examined various settings including weighted L2L_2-norm, LL_\infty norm, state aliasing, and state coverage.
result Established optimal asymptotic approximation factors for different norms and identified two instance-dependent factors for L2(μ)L_2(μ) norm.

This is a survey paper on Morse theory and the existence problem for closed geodesics. The free loop space plays a central role, since closed geodesics are critical points of the energy functional. As such, they can be analyzed through variational methods. The topics that we discuss include: Riemannian background, the …

2014-06-12abs ↗pdf ↗

In this note, we discuss embeddings of 33--manifolds via open books. First we show that every open book of every closed orientable 33--manifold admits an open book embedding in any open book decompistion of S2×S3S^2 \times S^3 and S2×~S3S^2 \widetilde{\times} S^3 with the page a disk bundle over S2S^2 and monodromy the iden…

2018-06-26abs ↗pdf ↗

We consider open, oriented 3-manifolds which are infinite connected sums of closed 3-manifolds. We introduce some topological invariants for these manifolds and obtain a classification in the case where there are only finitely many summands up to diffeomorphism. This result encompasses both the Kneser-Milnor Prime Deco…

2020-01-31abs ↗pdf ↗

Automatic summarization of natural language is a current topic in computer science research and industry, studied for decades because of its usefulness across multiple domains. For example, summarization is necessary to create reviews such as this one. Research and applications have achieved some success in extractive …

2018-12-18abs ↗pdf ↗

Study of Sasaki groups vs Kähler groups, showing distinct behaviors.

problem Comparing fundamental groups of Sasaki and Kähler manifolds.
method Analysis of properties and behavior of Sasaki groups compared to Kähler groups.
result Sasaki groups exhibit distinct behavior from Kähler groups, not closed under direct products, and have upper bounds on dimension.

We introduce a combinatorial model based on measured foliations in surfaces which captures the phenomenology of open/closed string interactions. The predicted equations are derived in this model, and new equations can be discovered as well. In particular, several new equations together with known transformations genera…

2006-03-20abs ↗pdf ↗

Estimates the rational homological dimension of Riemann surfaces with boundary and marked points.

problem Estimating the homological dimensions of Riemann surfaces with boundary and marked points.
method Developed an estimate for the rational homological dimension of Riemann surfaces with possible boundary and marked points.
result Provided an estimate for the rational homological dimension of Riemann surfaces with boundary and marked points.

CICLAD efficiently mines frequent closed itemsets from data streams with minimal memory usage.

problem Mining frequent closed itemsets from data streams is resource-intensive.
method CICLAD is an intersection-based sliding-window FCI miner that optimizes memory usage while maintaining performance.
result CICLAD achieves significantly lower memory footprint compared to existing methods.

A fundamental task in kernel methods is to pick nodes and weights, so as to approximate a given function from an RKHS by the weighted sum of kernel translates located at the nodes. This is the crux of kernel density estimation, kernel quadrature, or interpolation from discrete samples. Furthermore, RKHSs offer a conven…

2020-02-22abs ↗pdf ↗

In unsupervised learning, dimensionality reduction is an important tool for data exploration and visualization. Because these aims are typically open-ended, it can be useful to frame the problem as looking for patterns that are enriched in one dataset relative to another. These pairs of datasets occur commonly, for ins…

2018-11-14abs ↗pdf ↗

Motivated by the algebraic open-closed string models, we introduce and discuss an infinite-dimensional counterpart of the open-closed Hurwitz theory describing branching coverings generated both by the compact oriented surfaces and by the foam surfaces. We manifestly construct the corresponding infinite-dimensional equ…

2012-10-25abs ↗pdf ↗

We study b-arc foliation change and exchange move of open book foliations which generalize the corresponding operations in braid foliation theory. We also define a bypass move as an analogue of Honda's bypass attachment operation. As applications, we study how open book foliations change under a stabilization of the op…

2013-09-17abs ↗pdf ↗

In earlier studies, the estimation of the volatility of a stock using information on the daily opening, closing, high and low prices has been developed; the additional information in the high and low prices can be incorporated to produce unbiased (or near-unbiased) estimators with substantially lower variance than the …

2008-04-01abs ↗pdf ↗

This paper clarifies Bitcoin's volatility and predictability across daily, weekly, and monthly scales.

problem Clarify Bitcoin's volatility and predictability across different time scales.
method Using daily, weekly, and monthly closing prices and log-returns data, analyze volatility and predictability.
result Bitcoin exhibits high volatility and high predictability, with different behaviors at different time scales.

We first investigate the evolution of opening and closing auctions volumes of US equities along the years. We then report dynamical properties of pre-auction periods: the indicative match price is strongly mean-reverting because the imbalance is; the final auction price reacts to a single auction order placement or can…

2018-02-06abs ↗pdf ↗

This paper proposes a method to use deep neural networks as end-to-end open-set classifiers. It is based on intra-class data splitting. In open-set recognition, only samples from a limited number of known classes are available for training. During inference, an open-set classifier must reject samples from unknown class…

2019-03-12abs ↗pdf ↗

We discuss a Pareto macro-economy (a) in a closed system with fixed total wealth and (b) in an open system with average mean wealth and compare our results to a similar analysis in a super-open system (c) with unbounded wealth. Wealth condensation takes place in the social phase for closed and open economies, while it …

2001-01-05abs ↗pdf ↗