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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.

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2865728581,144 · Jun 202019922001200920172026
48 results for state space approximations

State spaces of multifactor approximations of nonnegative Volterra processes are linear transformations of the nonnegative orthant.

problem Characterizing state spaces of multifactor approximations of nonnegative Volterra processes.
method Explicit linear transformation of the nonnegative orthant.
result State spaces of multifactor approximations of nonnegative Volterra processes are given by explicit linear transformation of the nonnegative orthant.

The method approximates stationary distributions of Markov models by truncating irrelevant states.

problem Computing the stationary distribution of complex Markov models is computationally challenging.
method A state-space lumping scheme that aggregates states in a grid structure, iteratively refining the state-space.
result The method provides a well-justified finite-state projection tailored to the stationary behavior of Markov models.

Combines pseudo-point and state space approximations for scalable GPs.

problem Handling large numbers of off-the-grid spatial data-points and long time-series.
method Combines pseudo-point approximations for spatial data with state space GP approximations for temporal data.
result Combined approach is more scalable and applicable to a greater range of spatio-temporal problems.

Fluid approximations have seen great success in approximating the macro-scale behaviour of Markov systems with a large number of discrete states. However, these methods rely on the continuous-time Markov chain (CTMC) having a particular population structure which suggests a natural continuous state-space endowed with a…

2019-01-31abs ↗pdf ↗

Policy gradient methods with aggregated states can achieve better performance than approximate policy iteration.

problem Approximation errors in policy and value function approximations.
method State-aggregated representations and policy gradient methods.
result Policy gradient methods can achieve a per-period regret bounded by ε, while approximate policy iteration and value iteration have a higher regret.

A new method learns state and proposal dynamics in state-space models using neural networks.

problem Inference in non-linear state-space models.
method StateMixNN method using neural networks for proposal and transition distributions.
result Significantly improved recovery of hidden state, especially in highly non-linear scenarios.

HiPPO-Prophecy models can learn dynamical systems without fine-tuning.

problem Learning dynamical systems in context without fine-tuning parameters.
method Introduced a novel weight construction for SSMs that approximates derivatives of input signals.
result Discrete SSMs can predict the next state of any dynamical system after observing previous states.

Efficient RL in large POMDPs with latent determinism and embeddings.

problem Efficient reinforcement learning in large-scale POMDPs with latent states and observations.
method Conditional Hilbert space embeddings, linear optimal QQ-function, deterministic latent transitions, gap assumption.
result Computationally and statistically efficient algorithm for exact optimal policy.

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.

Robust state-space radio interferometric imaging using Stochastic Approximation Expectation Maximization

problem Improving state-space radio interferometric imaging in the presence of heavy-tailed noise
method Stochastic Approximation Expectation Maximization
result Significant improvement in reconstruction fidelity and robustness to radio-frequency interference

When using reinforcement learning (RL) algorithms to evaluate a policy it is common, given a large state space, to introduce some form of approximation architecture for the value function (VF). The exact form of this architecture can have a significant effect on the accuracy of the VF estimate, however, and determining…

2017-03-03abs ↗pdf ↗

Real Time Dynamic Programming (RTDP) is an online algorithm based on Dynamic Programming (DP) that acts by 1-step greedy planning. Unlike DP, RTDP does not require access to the entire state space, i.e., it explicitly handles the exploration. This fact makes RTDP particularly appealing when the state space is large and…

2019-09-10abs ↗pdf ↗

Bayesian state and parameter estimation for nonlinear models using variational methods.

problem Estimating states and parameters for nonlinear state-space models.
method Variational approach to approximate the intractable Bayesian distribution, resulting in an optimisation problem.
result The proposed method efficiently computes Bayesian estimates for nonlinear models, outperforming Hamiltonian Monte Carlo in numerical examples.

Signal temporal logic (STL) is an expressive language to specify time-bound real-world robotic tasks and safety specifications. Recently, there has been an interest in learning optimal policies to satisfy STL specifications via reinforcement learning (RL). Learning to satisfy STL specifications often needs a sufficient…

2020-01-26abs ↗pdf ↗

New algorithms reduce complexity for learning in MDPs with entropy regularization.

problem Efficient learning for MDPs with large or continuous state and action spaces.
method Multilevel Monte Carlo (MLMC) algorithms integrating fixed-point iteration and stochastic approximation of the Bellman operator.
result MLMC with unbiased approximation of the Bellman operator achieves polynomial sample complexity.

We prove a conjecture about approximating Gaussian Processes on one dimension.

problem Computational scaling issues with Gaussian Processes on one dimension.
method Developed a new family of state-space models (LEG) to approximate any stationary GP on one dimension.
result Proved that any stationary GP on one dimension can be approximated using the LEG family.

We seek to learn an effective policy for a Markov Decision Process (MDP) with continuous states via Q-Learning. Given a set of basis functions over state action pairs we search for a corresponding set of linear weights that minimizes the mean Bellman residual. Our algorithm uses a Kalman filter model to estimate those …

2013-09-26abs ↗pdf ↗

We describe a Markov latent state space (MLSS) model, where the latent state distribution is a decaying mixture over multiple past states. We present a simple sampling algorithm that allows to approximate such high-order MLSS with fixed time and memory costs.

2017-11-08abs ↗pdf ↗

A new method for Gaussian filtering using gradient flows and Wasserstein metrics.

problem Approximating Gaussian and mixture-of-Gaussians filtering for complex systems.
method Variational approximation via gradient-flow representation on Wasserstein metric space.
result Competitive performance in posterior representation and parameter estimation for systems with multiplicative noise and multi-modal distributions.

Improved state estimation in nonlinear models using amortized backward variational inference.

problem State estimation in general state-space models.
method Amortized backward variational inference with neural network parameters.
result Linear growth of variational approximation error in number of observations.

New RL algorithm tackles large state spaces using optimistic function approximation.

problem Challenges in reinforcement learning with large state spaces and modern function approximators.
method Optimistic modification of least-squares value iteration algorithm for kernel functions or overparameterized neural networks.
result Polynomial runtime and sample complexity, independent of the number of states, with ildeO(δFH2T) ilde{\mathcal{O}}(δ_{\mathcal{F}} H^2 \sqrt{T}) regret.

The paper introduces Causal Neural Operators to approximate operators in stochastic analysis.

problem Leveraging temporal structure in non-linear operators for deep learning models.
method Designing a deep learning model framework for infinite-dimensional linear metric spaces.
result Causal Neural Operators can uniformly approximate Hölder or smooth trace class operators.

New RL method handles large state-action spaces with complex models.

problem Complex models and large state-action spaces in reinforcement learning.
method π-KRVI, an optimistic modification of least-squares value iteration using kernel ridge regression.
result First order-optimal regret guarantees under general settings, improving over state of the art.

Several approximate policy iteration schemes without value functions, which focus on policy representation using classifiers and address policy learning as a supervised learning problem, have been proposed recently. Finding good policies with such methods requires not only an appropriate classifier, but also reliable e…

2008-05-14abs ↗pdf ↗

Study agnostic RL in large state spaces with weak function approximation.

problem Statistical intractability of agnostic policy learning in various environments.
method Investigates agnostic policy learning with different forms of environment access.
result Agnostic policy learning remains statistically intractable with certain forms of environment access.

Active inference is a process theory of the brain that states that all living organisms infer actions in order to minimize their (expected) free energy. However, current experiments are limited to predefined, often discrete, state spaces. In this paper we use recent advances in deep learning to learn the state space an…

2020-01-30abs ↗pdf ↗

Gaussian state space models have been used for decades as generative models of sequential data. They admit an intuitive probabilistic interpretation, have a simple functional form, and enjoy widespread adoption. We introduce a unified algorithm to efficiently learn a broad class of linear and non-linear state space mod…

2016-09-30abs ↗pdf ↗

State-space models (SSMs) provide a flexible framework for modelling time-series data. Consequently, SSMs are ubiquitously applied in areas such as engineering, econometrics and epidemiology. In this paper we provide a fast approach for approximate Bayesian inference in SSMs using the tools of deep learning and variati…

2018-11-20abs ↗pdf ↗

When using reinforcement learning (RL) algorithms it is common, given a large state space, to introduce some form of approximation architecture for the value function (VF). The exact form of this architecture can have a significant effect on an agent's performance, however, and determining a suitable approximation arch…

2017-03-23abs ↗pdf ↗

New variational inference approach using Hilbert space for robotic state estimation.

problem Robotic state estimation with high-dimensional data.
method Variational inference reformulated in a Bayesian Hilbert space, using iterative projection.
result Variational inference can be seen as iterative projection in Euclidean space.

We provide a comprehensive overview and tooling for GP modeling with non-Gaussian likelihoods using state space methods. The state space formulation allows for solving one-dimensional GP models in O(n)\mathcal{O}(n) time and memory complexity. While existing literature has focused on the connection between GP regression …

2018-02-13abs ↗pdf ↗

A new method learns complex dynamical systems from data efficiently.

problem Learning complex dynamical systems from large-scale data efficiently.
method Low-rank structured variational autoencoding framework for nonlinear Gaussian state-space models.
result Consistently demonstrates better predictive capabilities compared to other models.

Empirical mode modeling improves state-space analysis of noisy data.

problem Analyzing nonlinear systems with noisy data.
method Combining empirical mode decomposition with empirical dynamic modeling.
result Empirical mode modeling enhances state-space representations in noisy data.

Continuous state spaces and stochastic, switching dynamics characterize a number of rich, realworld domains, such as robot navigation across varying terrain. We describe a reinforcementlearning algorithm for learning in these domains and prove for certain environments the algorithm is probably approximately correct wit…

2012-06-13abs ↗pdf ↗

Estimates quantum cohomology complexity for Fano varieties and homogeneous spaces.

problem Quantum cohomology complexity estimation for compact symplectic manifolds.
method Estimates the number of states with finite approximate complexity for Fano complete intersections and (co)minuscule homogeneous varieties.
result Sharp upper bound for the dimension of the space spanned by states with finite complexity for Gr(2, n).