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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.

168,742 papers · 148 categories

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48 results for metric state spaces

The volume of the quantum mechanical state space over nn-dimensional real, complex and quaternionic Hilbert-spaces with respect to the canonical Euclidean measure is computed, and explicit formulas are presented for the expected value of the determinant in the general setting too. The case when the state space is endo…

2006-04-14abs ↗pdf ↗

ZoomRL learns efficient strategies for large state-action spaces using a metric.

problem Handling large state-action spaces in reinforcement learning.
method ZoomRL leverages continuous bandits to adaptively discretize the joint space.
result Achieves worst-case regret of $ ilde{O}(H^{ rac{5}{2}} K^{ rac{d+1}{d+2}})$.

We study online reinforcement learning for finite-horizon deterministic control systems with {\it arbitrary} state and action spaces. Suppose that the transition dynamics and reward function is unknown, but the state and action space is endowed with a metric that characterizes the proximity between different states and…

2019-05-05abs ↗pdf ↗

State-space systems generate probabilistic dependencies between inputs and outputs.

problem Understanding probabilistic dependencies in state-space systems.
method Introducing a probabilistic framework and proving sufficient conditions for output existence and uniqueness.
result State-space systems can generate probabilistic dependencies, even without functional relations.

Kernel-UCBVI algorithm balances exploration and exploitation in metric state-action spaces.

problem Exploration-exploitation dilemma in finite-horizon reinforcement learning with metric state-action spaces.
method Kernel-UCBVI, leveraging smoothness and kernel estimators of rewards and transitions.
result First regret bound for kernel-based RL using smoothing kernels, O(H3K2d/(2d+1))O(H^3 K^{2d/(2d+1)}).

Model-free Reinforcement Learning (RL) algorithms such as Q-learning [Watkins, Dayan 92] have been widely used in practice and can achieve human level performance in applications such as video games [Mnih et al. 15]. Recently, equipped with the idea of optimism in the face of uncertainty, Q-learning algorithms [Jin, Al…

2019-05-01abs ↗pdf ↗

KeRNS tackles non-stationary reinforcement learning in metric spaces.

problem Non-stationary reinforcement learning in metric spaces.
method KeRNS uses time-dependent kernels to model non-stationary Markov Decision Processes (MDPs).
result KeRNS achieves a regret bound that scales with the covering dimension and total variation of the MDP.

The study examines a semi-symmetric metric connection in perfect fluid space-time and phantom barriers.

problem Investigating the properties of semi-symmetric metric connections in perfect fluid space-time.
method Using concircularly semi-symmetric metric connections, the study derives conditions for quasi-Einstein manifolds and examines the scalar curvature of perfect fluid space-times.
result The study proves that in a perfect fluid space-time, the scalar curvature is constant and represents a phantom barrier.

A new metric based on hitting probabilities for directed graphs and Markov chains.

problem Lack of metrics specifically adapted to asymmetric structure of directed graphs and Markov chains.
method Metric based on hitting probabilities, insensitive to shortest and average walk distances.
result New structural theory of directed graphs and utility for various applications.

Efficient algorithm for reinforcement learning in large state-action spaces with adaptive discretization.

problem Efficient reinforcement learning in large, potentially continuous state-action spaces.
method Adaptive QQ-learning policy with data-driven adaptive discretization.
result Demonstrates improved performance compared to existing methods, especially in adapting to the problem's structure.

A new method estimates multi-dimensional value distributions using Hilbert space embeddings.

problem Estimating value distributions in complex, multi-dimensional reinforcement learning settings.
method Hilbert space mappings and kernel mean embeddings to estimate the kernel mean embedding of multi-dimensional value distributions.
result Uniform convergence guarantees and robust off-policy evaluation demonstrated in simulations.

I consider compact metric spaces which admit intrinsic isometries to Euclidean d-space. The main result roughly states that the class of these spaces coincides with class of inverse limits of Euclidean d-polyhedra.

2010-03-29abs ↗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.

The main result of this article states that the (K;N)-cone over some metric measure space satisfies the reduced Riemannian curvature-dimension condition RCD^*(KN;N+1) if and only if the underlying space satisfies RCD^*(N-1;N). The proof uses a characterization of reduced Riemannian curvature-dimension bounds by Bochner…

2013-11-06abs ↗pdf ↗

Geometric approach to quantum thermodynamics models state spaces and processes.

problem Quantum thermodynamics in the regime of non-equilibrium states.
method Contact geometry and principal fiber bundles to model quantum state spaces and processes.
result Geometric formulation reveals the fundamental thermodynamic relations and unattainability of the third law.

In this paper we study isometry-invariant Finsler metrics on inner product spaces over R\mathbb{R} or C\mathbb{C}, i.e. the Finsler metrics which do not change under the action of all isometries of the inner product space. We give a new proof of the analytic description of all such metrics. In this article the most g…

2017-08-25abs ↗pdf ↗

Paper introduces a new framework to improve sample efficiency in POMDPs learning.

problem Challenges in off-policy evaluation for POMDPs, especially with hidden states.
method Exploits the metric structure of belief space to relax coverage assumptions.
result Unified analysis technique yields tighter error bounds and sample efficiency improvements.

Entangled bisimulation improves policy learning from visual input.

problem Learning generalizeable policies from visual input in the presence of visual distractions.
method Proposes entangled bisimulation, a bisimulation metric for continuous state and action spaces.
result Entangled bisimulation improves policy learning on the Distracting Control Suite (DCS).

On a compact spin manifold we study the space of Riemannian metrics for which the Dirac operator is invertible. The first main result is a surgery theorem stating that such a metric can be extended over the trace of a surgery of codimension at least three. We then prove that if non-empty the space of metrics with inver…

2006-03-01abs ↗pdf ↗

We consider the problem of metric learning for multi-view data and present a novel method for learning within-view as well as between-view metrics in vector-valued kernel spaces, as a way to capture multi-modal structure of the data. We formulate two convex optimization problems to jointly learn the metric and the clas…

2018-03-21abs ↗pdf ↗

Differentiable optimization bridges arbitrary metrics to tree metrics.

problem Designing algorithms to convert arbitrary metrics to tree metrics with guarantees.
method DeltaZero framework, leveraging differentiable Gromov hyperbolicity.
result DeltaZero consistently achieves state-of-the-art distortion on synthetic and real-world datasets.

New bounds for low-regularity Riemannian metrics defined via distributional curvature.

problem Establishing curvature bounds for Riemannian metrics of low regularity.
method Introducing a distributional version of sectional curvature for C1C^1 and C0C^0 metrics.
result New bounds for low-regularity metrics recover classical bounds in Alexandrov spaces.

In this paper we prove that for all n=4k2n=4k-2, k2k\ge2 there exists closed nn-dimensional Riemannian manifolds MM with negative sectional curvature that do not have the homotopy type of a locally symmetric space, such that π1(T<0(M))π_{1}(\mathcal{T}^{<0}(M)) is non-trivial. T<0(M)\mathcal{T}^{<0}(M) denotes the Teichmüller space…

2013-11-22abs ↗pdf ↗

Study finds all hyper-Kähler 4-manifolds with specific symmetries and structures.

problem Characterizing hyper-Kähler 4-manifolds with conformal Kähler structures.
method Analyzing twistor elementary states and locally flat spaces, showing compatibility and incompatibility of complex structures.
result Only hyper-Kähler 4-metric with a non-constant Killing-Yano tensor is the half-flat Taub-NUT instanton.

Our main result in this article is a compactness result which states that a noncollapsed sequence of asymptotically locally Euclidean (ALE) scalar-flat Kähler metrics on a minimal Kähler surface whose Kähler classes stay in a compact subset of the interior of the Kähler cone must have a convergent subsequence. As an ap…

2019-01-17abs ↗pdf ↗

A classical theorem, mainly due to Aleksandrov and Pogorelov, states that any Riemannian metric on S2S^2 with curvature K>1K>-1 is induced on a unique convex surface in H3H^3. A similar result holds with the induced metric replaced by the third fundamental form. We show that the same phenomenon happens with yet another …

2001-01-30abs ↗pdf ↗

It is well-known that the class of piecewise smooth curves together with a smooth Riemannian metric induces a metric space structure on a manifold. However, little is known about the minimal regularity needed to analyze curves and particularly to study length-minimizing curves where neither classical techniques such as…

2012-12-31abs ↗pdf ↗