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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.

168,695 papers · 148 categories

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85169254338 · Jun 202019922001200920172026
48 results for Normality assumption

A new Heckman selection model uses a bivariate contaminated normal distribution for more accurate data analysis.

problem Sample selection biases in econometric data analysis.
method Introduces a Heckman selection model using a bivariate contaminated normal distribution and presents an efficient ECM algorithm for parameter estimation.
result The proposed model outperforms normal and Student's t counterparts in real data analysis and simulation studies.

Normalizing flows are shown to be equivalent to Bayesian networks, revealing new insights.

problem Understanding the limitations and capabilities of normalizing flows.
method Revisiting normalizing flows as probabilistic graphical models and analyzing their structure.
result Normalizing flows can be reduced to Bayesian networks, revealing new insights into their structure and capabilities.

We consider the problem of providing nonparametric confidence guarantees for undirected graphs under weak assumptions. In particular, we do not assume sparsity, incoherence or Normality. We allow the dimension DD to increase with the sample size nn. First, we prove lower bounds that show that if we want accurate infe…

2013-09-26abs ↗pdf ↗

The study shows how to foliate convex hypersurfaces in affine space with constant curvature.

problem Finding convex hypersurfaces with constant Gauss-Kronecker curvature in affine space.
method Solving a Monge-Ampère equation with specific boundary conditions.
result Regular domains in affine space are foliated by complete convex hypersurfaces with constant Gauss-Kronecker curvature.

A new tree model, GRST, improves option pricing without log-normality assumptions.

problem Limitations of CRR binomial trees in valuing securities with early exercise characteristics.
method Gaussian Recombining Split Tree (GRST) that generates a discrete probability mass function approximating a Gaussian distribution.
result Option prices from GRST align closely with market prices.

The article explains the probabilistic method of default probability estimation by Pluto and Tasche.

problem Estimating default probabilities for portfolios with low default rates.
method Detailed derivation and explanation of the Pluto-Tasche method, including assumptions and inequalities.
result Clarification of borrower independence, conditional independence, and interaction between probability distributions.

New method constructs synthetic treatment groups without mean exchangeability assumption.

problem Violations of mean exchangeability assumption in randomized controlled trials.
method Weighted mixture of treatment groups from source populations, minimizing conditional maximum mean discrepancy.
result Asymptotic normality of synthetic treatment group estimator established.

We prove that every acyclic normal one-dimensional real Ambrosio-Kirchheim current in a Polish (i.e. complete separable metric) space can be decomposed in curves, thus generalizing the analogous classical result proven by S. Smirnov in Euclidean space setting. The same assertion is true for every complete metric space …

2013-03-22abs ↗pdf ↗

We establish normal forms for conformal vector fields on pseudo-Riemannian manifolds in the neighborhood of a singularity. For real-analytic Lorentzian manifolds, we show that the vector field is analytically linearizable or the manifold is conformally flat. In either case, the vector field is locally conjugate to a no…

2010-08-23abs ↗pdf ↗

Study reveals dynamics of neural networks with normalization, weight decay, and SGD.

problem Understanding the equilibrium condition in Spherical Motion Dynamics (SMD).
method Investigates SMD by exploring the cause of equilibrium condition, introducing assumptions, proposing angular update, and verifying theoretical results.
result Proves weight norm and angular update can converge at linear rate under given assumptions.

In this survey, a short introduction in the recent discovery of log-normally distributed market-technical trend data will be given. The results of the statistical evaluation of typical market-technical trend variables will be presented. It will be shown that the log-normal assumption fits better to empirical trend data…

2016-05-11abs ↗pdf ↗

It was conjectured, twenty years ago, the following result that would generalize the so-called rank rigidity theorem for homogeneous Euclidean submanifolds: let M^n, n>=2, be a full and irreducible homogeneous submanifold of the sphere SN1RNS^{N-1}\subset R^N and such that the normal holonomy group is not transitive (on t…

2013-06-10abs ↗pdf ↗

Paper explores whether gradient normalization can replace clipping for SGD in heavy-tailed noise.

problem Ensuring convergence of SGD in heavy-tailed noise.
method Revisits gradient clipping and normalization, proving their sufficiency and effectiveness.
result Gradient normalization alone is sufficient for nonconvex SGD convergence under smoothness assumptions.

On a manifold (Rn,e2udx2)(\mathbb{R}^n, e^{2u} |dx|^2), we say uu is normal if the QQ-curvature equation that uu satisfies (Δ)n2u=Qgenu(-Δ)^{\frac{n}{2}} u = Q_g e^{nu} can be written as the integral form u(x)=1cnRnlogyxyQg(y)enu(y)dy+Cu(x)=\frac{1}{c_n}\int_{\mathbb R^n}\log\frac{|y|}{|x-y|}Q_g(y)e^{nu(y)}dy+C. In this paper, we show that the integrability assum…

2017-07-14abs ↗pdf ↗

New bounds on self-normalized martingales improve online linear regression performance.

problem Improving regret bounds in online linear regression.
method Characterizing scale-invariant bounds on self-normalized martingales.
result For d=1d=1, O(logT)O(\log T) doubly-uniform regret is possible; for d>1d>1, sublinear doubly-uniform regret is impossible.

We generalize the Weinstein-Moser theorem on the existence of nonlinear normal modes (i.e., periodic orbits) near an equilibrium in a Hamiltonian system to a theorem on the existence of relative periodic orbits near a relative equilibrium in a Hamiltonian system with continuous symmetries. More specifically we signific…

1999-06-01abs ↗pdf ↗

As bandit algorithms are increasingly utilized in scientific studies and industrial applications, there is an associated increasing need for reliable inference methods based on the resulting adaptively-collected data. In this work, we develop methods for inference on data collected in batches using a bandit algorithm. …

2020-02-08abs ↗pdf ↗

Yau's Affine Normal Descent optimizes smooth unconstrained problems with geometrically adapted directions.

problem Optimizing smooth unconstrained problems with geometrically adapted directions.
method Yau's Affine Normal Descent (YAND) uses the equi-affine normal of level-set hypersurfaces as search directions.
result YAND converges globally under standard smoothness assumptions and locally quadratically near nondegenerate minimizers.

INF-clip optimizes heavy-tailed MAB problems with improved performance.

problem Optimizing multi-armed bandit problems with heavy-tailed rewards.
method INF-clip algorithm for adversarial and stochastic heavy-tailed MAB settings.
result INF-clip is optimal for linear and non-linear heavy-tailed stochastic MAB problems.

This paper considers options pricing when the assumption of normality is replaced with that of the symmetry of the underlying distribution. Such a market affords many equivalent martingale measures (EMM). However we argue (as in the discrete-time setting of Klebaner and Landsman, 2007) that an EMM that keeps distributi…

2014-02-07abs ↗pdf ↗

We describe algorithms for learning Bayesian networks from a combination of user knowledge and statistical data. The algorithms have two components: a scoring metric and a search procedure. The scoring metric takes a network structure, statistical data, and a user's prior knowledge, and returns a score proportional to …

2013-02-27abs ↗pdf ↗

Anomaly detection is a challenging task that frequently arises in practically all areas of industry and science, from fraud detection and data quality monitoring to finding rare cases of diseases and searching for new physics. Most of the conventional approaches to anomaly detection, such as one-class SVM and Robust Au…

2019-12-19abs ↗pdf ↗

We study sharp asymptotics of the first eigenvalue on Riemannian surfaces obtained from a fixed Riemannian surface by attaching a collapsing flat handle or cross cap to it. Through a careful choice of parameters this construction can be used to strictly increase the first eigenvalue normalized by area if the initial su…

2019-09-06abs ↗pdf ↗

Lower bounds on average normal curvature for submanifolds in Riemannian domains.

problem Finding bounds on the average normal curvature of submanifolds in Riemannian domains.
method Using an invariant measuring optimal nn-trace convexity under unit-gradient normalization.
result Lower bounds for the average normal curvature expressed in terms of an invariant.

New algorithm tackles nonconvex machine learning problems with adaptive normalization and independent sampling.

problem Nonconvex machine learning problems with generalized-smoothness.
method Adaptive gradient normalization, independent sampling, and gradient clipping.
result Achieves an O(ε^(-4)) sample complexity for fast convergence.

Flow IV uses IVs to infer counterfactuals in complex models.

problem Identifying causal effects and counterfactual reasoning in nonseparable outcome models.
method Utilizes instrumental variables and normalizing flows to estimate and infer counterfactual outcomes.
result Identifies a method to make causal inferences from observed data in nonseparable models.

The paper strengthens the classical result of MLE convergence to a Gaussian distribution.

problem The classical result of MLE convergence to a Gaussian distribution.
method Sub-Gaussian concentration and entropic normality of the normalized MLE.
result Entropic central limit theorem for a smoothed version of the estimator.

Develops methods for constructing parameter priors in DAG models.

problem Constructing parameter priors for model choice among DAG models.
method Introduces assumptions and methods for parameter priors construction and marginal likelihood computation.
result The only parameter prior for complete Gaussian DAG models that satisfies assumptions is the normal-Wishart distribution.

For a subRiemannian manifold and a given Riemannian extension of the metric, we define a canonical global connection. This connection coincides with both the Levi-Civita connection on Riemannian manifolds and the Tanaka-Webster connection on strictly pseudoconvex CR manifolds. We define a notion of normality generalizi…

2009-12-17abs ↗pdf ↗

Employing Morse theory for the global control of monodromy and the method of analytic discs for local extension, we establish a version of the global Hartogs extension theorem in a singular setting: for every domain D of an (n-1)-complete normal complex space X of pure dimension n >= 2 and for every compact set K in D …

2007-04-24abs ↗pdf ↗

The construction of topological index maps for equivariant families of Dirac operators requires factoring a general smooth map through maps of a very simple type: zero sections of vector bundles, open embeddings, and vector bundle projections. Roughly speaking, a normally non-singular map is a map together with such a …

2009-08-11abs ↗pdf ↗