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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.

168,694 papers · 148 categories

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20395978 · May 202619922001200920172026
48 results for Walk Index

Several known results, by Rivin, Calegari-Maher and Sisto, show that an element φnOut(Fr)φ_n\in Out(F_r), obtained after nn steps of a simple random walk on Out(Fr)Out(F_r), is fully irreducible with probability tending to 1 as nn\to\infty. In this paper we construct a natural "train-track directed" random walk W\mathcal W on $…

2014-09-29abs ↗pdf ↗

We prove a sharp estimate on the expected value of the integral of the index of a simple random walk on the square or triangular lattice. This gives new lower bounds on the averaged Dehn function, which measures the expected area needed to fill a random curve with a disc.

2008-07-14abs ↗pdf ↗

Graphs can model interactions between vertices, but how well depends on graph structure.

problem Lack of formal characterization of GNNs' ability to model interactions between vertices.
method Formalized interaction strength using separation rank and quantified it for different partitions of vertices.
result GNNs' ability to model interactions is primarily determined by the partition's walk index.

XGBoost predicts NEPSE Index log returns with low error and high directional accuracy.

problem Forecasting daily log-returns in the NEPSE Index with high accuracy.
method XGBoost machine learning, feature engineering, hyperparameter optimization, walk-forward validation.
result Optimal XGBoost configuration achieves lowest log-return RMSE and MAE.

Data-driven methods link graphon limits to random walks and spectral clustering.

problem Clustering signals evolving over time with graphon limits.
method Transfer operators, Koopman and Perron-Frobenius, for estimating graphon from signal data.
result Spectral clustering can be extended to graphons, reconstructing transition densities and graphons.

It is known that every infinite index quasi-convex subgroup HH of a non-elementary hyperbolic group GG is a free factor in a larger quasi-convex subgroup of GG. We give a probabilistic generalization of this result. That is, we show that when RR is a subgroup generated by independent random walks in GG, then $\lan…

2019-09-24abs ↗pdf ↗

Gittins index optimizes decision-making under uncertainty, even in complex scenarios.

problem Optimal decision-making under uncertainty.
method Gittins index optimizes allocation of resources among uncertain options.
result Gittins index can be effectively applied to practical problems, including Bayesian optimization and queue latency minimization.

We investigate the statistics of records in a random sequence {xB(0)=0,xB(1),,xB(n)=xB(0)=0}\{x_B(0)=0,x_B(1),\cdots, x_B(n)=x_B(0)=0\} of nn time steps. The sequence xB(k)x_B(k)'s represents the position at step kk of a random walk `bridge' of nn steps that starts and ends at the origin. At each step, the increment of the position is a random ju…

2015-05-22abs ↗pdf ↗

We study the volatility of the MIB30-stock-index high-frequency data from November 28, 1994 through September 15, 1995. Our aim is to empirically characterize the volatility random walk in the framework of continuous-time finance. To this end, we compute the index volatility by means of the log-return standard deviatio…

1999-03-14abs ↗pdf ↗

Quantum stochastic walks optimize portfolios by leveraging financial networks, improving Sharpe ratios and reducing turnover.

problem Optimizing portfolios in noisy financial markets with superior risk-adjusted returns.
method Embed assets in a weighted graph, using quantum stochastic walks to derive optimal portfolio weights from the stationary distribution.
result Quantum stochastic walks can lift Sharpe ratios by up to 27% and reduce turnover from 480% to 2-90%.

Randomized control methods improve asset pricing and performance analysis.

problem Challenges in drawing inferences from traditional random portfolios in performance evaluation.
method Geometric random walks and Markov chain Monte Carlo methods to construct flexible control groups.
result Captured premia associated with size, value, quality, and momentum in a constrained setting.

We construct a new type of quantum walks on simplicial complexes as a natural extension of the well-known Szegedy walk on graphs. One can numerically observe that our proposing quantum walks possess linear spreading and localization as in the case of the Grover walk on lattices. Moreover, our numerical simulation sugge…

2015-07-05abs ↗pdf ↗

We propose a random walk model of asset returns where the parameters depend on market stress. Stress is measured by, e.g., the value of an implied volatility index. We show that model parameters including standard deviations and correlations can be estimated robustly and that all distributions are approximately normal.…

2013-10-16abs ↗pdf ↗

The paper tackles attributing forecast gaps in complex model suites.

problem Attributing forecast gaps to individual component models in complex model suites.
method Formalized walk analysis, adapted LMDI and Shapley value approaches.
result Developed efficient formulas for gap attribution in practical portfolio-scale examples.

This paper presents VEC-NBT, a variation on the unsupervised graph clustering technique VEC, which improves upon the performance of the original algorithm significantly for sparse graphs. VEC employs a novel application of the state-of-the-art word2vec model to embed a graph in Euclidean space via random walks on the n…

2017-08-26abs ↗pdf ↗

We propose and analyze two new MCMC sampling algorithms, the Vaidya walk and the John walk, for generating samples from the uniform distribution over a polytope. Both random walks are sampling algorithms derived from interior point methods. The former is based on volumetric-logarithmic barrier introduced by Vaidya wher…

2017-10-23abs ↗pdf ↗

The paper introduces walks with jumps for modeling neuron activity in hyperbolic space.

problem Encoding neuron activity sequences in hyperbolic space.
method Introducing walks with jumps in hyperbolic geometry to model neuron activity.
result Endpoints of walks with jumps do not fully encode the sequence of jump times.

Unified view on random walk and Weisfeiler-Leman kernels, improving accuracy.

problem Improving graph kernel methods for better classification accuracy.
method Define and analyze walk-based node refinement methods, relate to Weisfeiler-Leman test, and introduce new walk-based kernels.
result Walk-based kernels are as expressive as Weisfeiler-Leman subtree kernel but support non-strict neighborhood comparison.

Local limit theorem for random walks on hyperbolic groups with parabolic subgroups.

problem Analyzing the behavior of random walks on relatively hyperbolic groups.
method Study of convergent random walks with finite derivative of Green function at spectral radius.
result Proves a local limit theorem for the probability of returning to the origin.

Study diffusions and random walks on hyperbolic spaces, focusing on their Martin boundaries.

problem Understanding diffusions and random walks on hyperbolic spaces.
method Analyzing specific diffusions and random walks on hyperbolic spaces, examining their Martin boundaries.
result Characterized the Martin boundaries of diffusions and random walks on hyperbolic spaces.

Random walks on hyperbolic spaces show linear growth in translation lengths.

problem Investigate the growth of translation lengths in random walks on hyperbolic spaces.
method Prove linear growth without moment conditions and apply to Teichmüller spaces.
result Linear growth of translation lengths in random walks on hyperbolic spaces.

Market economy closely connects aspects to all walks of life. The stock forecast is one of task among studies on the market economy. However, information on markets economy contains a lot of noise and uncertainties, which lead economy forecasting to become a challenging task. Ensemble learning and deep learning are the…

2019-09-19abs ↗pdf ↗

The paper examines random walks on metric spaces and finds commensurable subgroups.

problem Determining commensurable subgroups via stationary measures in metric spaces.
method Analyzing random walks on isometry groups of metric spaces with non-singular stationary measures.
result Subgroups generated by random walks are commensurable under mild conditions.

This work estimates edge weights of edge-reinforced random walks using observed data.

problem Statistical estimation of edge weights in edge-reinforced random walks.
method Proposes an estimator based on the generalized method of moments using the magic formula and hyperbolic Gaussian structure.
result Analyzes the sample complexity of the proposed estimator.

Deviation inequalities and limit laws for random walks on metric spaces.

problem Understanding random walks on metric spaces with contracting isometries.
method Adapting Gouëzel's pivotal time construction to establish deviation inequalities.
result Exponential bounds and limit laws for random walks on mapping class groups and CAT(0) spaces.

Random walks on Fuchsian Schottky groups have harmonic measures with lower dimension.

problem Understanding the dimensionality of harmonic measures for random walks.
method Analyzing finite range random walks on Fuchsian Schottky groups.
result Harmonic measures have dimension strictly less than the limit set's Hausdorff dimension.

UniNet efficiently learns network representations from large graphs.

problem Efficiently learning network representations from large graphs.
method Metropolis-Hastings sampling for efficient edge sampling and random walk model abstraction.
result UniNet outperforms existing NRL models on billion-edge networks.

We study the statistics of the number of records R_{n,N} for N identical and independent symmetric discrete-time random walks of n steps in one dimension, all starting at the origin at step 0. At each time step, each walker jumps by a random length drawn independently from a symmetric and continuous distribution. We co…

2012-04-23abs ↗pdf ↗

We review statistical properties of models generated by the application of a (positive and negative order) fractional derivative operator to a standard random walk and show that the resulting stochastic walks display slowly-decaying autocorrelation functions. The relation between these correlated walks and the well-kno…

2008-06-19abs ↗pdf ↗

We introduce the geodesic walk for sampling Riemannian manifolds and apply it to the problem of generating uniform random points from polytopes in R^n specified by m inequalities. The walk is a discrete-time simulation of a stochastic differential equation (SDE) on the Riemannian manifold equipped with the metric induc…

2016-06-15abs ↗pdf ↗