Search Results for author: Martin Keller-Ressel

Found 13 papers, 3 papers with code

Emergence of heavy tails in homogenized stochastic gradient descent

no code implementations2 Feb 2024 Zhe Jiao, Martin Keller-Ressel

It has repeatedly been observed that loss minimization by stochastic gradient descent (SGD) leads to heavy-tailed distributions of neural network parameters.

Hyperbolic Deep Learning in Computer Vision: A Survey

no code implementations11 May 2023 Pascal Mettes, Mina Ghadimi Atigh, Martin Keller-Ressel, Jeffrey Gu, Serena Yeung

In this paper, we provide a categorization and in-depth overview of current literature on hyperbolic learning for computer vision.

Representation Learning

State space decomposition and classification of term structure shapes in the two-factor Vasicek model

no code implementations24 Mar 2023 Martin Keller-Ressel, Felix Sachse

Using the concept of envelopes we show how to divide the state space $\RR^2$ of the two-factor Vasicek model into regions of identical term-structure shape.

W-shaped implied volatility curves in a variance-gamma mixture model

no code implementations29 Sep 2022 Martin Keller-Ressel

In liquid option markets, W-shaped implied volatility curves have occasionally be observed.

Bartlett's Delta revisited: Variance-optimal hedging in the lognormal SABR and in the rough Bergomi model

no code implementations27 Jul 2022 Martin Keller-Ressel

We derive analytic expressions for the variance-optimal hedging strategy and its mean-square hedging error in the lognormal SABR and in the rough Bergomi model.

Strain-Minimizing Hyperbolic Network Embeddings with Landmarks

no code implementations14 Jul 2022 Martin Keller-Ressel, Stephanie Nargang

We introduce L-hydra (landmarked hyperbolic distance recovery and approximation), a method for embedding network- or distance-based data into hyperbolic space, which requires only the distance measurements to a few 'landmark nodes'.

A Theory of Hyperbolic Prototype Learning

no code implementations15 Oct 2020 Martin Keller-Ressel

We introduce Hyperbolic Prototype Learning, a type of supervised learning, where class labels are represented by ideal points (points at infinity) in hyperbolic space.

regression

The hyperbolic geometry of financial networks

no code implementations1 May 2020 Martin Keller-Ressel, Stephanie Nargang

Based on data from the European banking stress tests of 2014, 2016 and the transparency exercise of 2018 we demonstrate for the first time that the latent geometry of financial networks can be well-represented by geometry of negative curvature, i. e., by hyperbolic geometry.

The classification of term structure shapes in the two-factor Vasicek model -- a total positivity approach

no code implementations13 Aug 2019 Martin Keller-Ressel

We provide a full classification of all attainable term structure shapes in the two-factor Vasicek model of interest rates.

Hydra: A method for strain-minimizing hyperbolic embedding of network- and distance-based data

no code implementations21 Mar 2019 Martin Keller-Ressel, Stephanie Nargang

We introduce hydra (hyperbolic distance recovery and approximation), a new method for embedding network- or distance-based data into hyperbolic space.

Detecting independence of random vectors: generalized distance covariance and Gaussian covariance

1 code implementation21 Nov 2017 Björn Böttcher, Martin Keller-Ressel, René L. Schilling

Distance covariance is a quantity to measure the dependence of two random vectors.

Probability Statistics Theory Statistics Theory

Distance multivariance: New dependence measures for random vectors

1 code implementation21 Nov 2017 Björn Böttcher, Martin Keller-Ressel, René L. Schilling

We introduce two new measures for the dependence of $n \ge 2$ random variables: distance multivariance and total distance multivariance.

Probability Statistics Theory Statistics Theory 62H20, 60E10, 62G10, 62G15, 62G20

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