75 citations · 236 across the 75 of their papers we have counts for
58 papers · 1 filter
Lower path regularity in all dimensions
Michael Hinz, Jonas M. Tölle, Lauri Viitasaari
We prove precise almost sure lower path regularity results for a wide class of stochastic processes in all space dimensions . Examples include Gaussian processes, in parti…
Error analysis for learning fractional stochastic differential equations with applications in neural approximations
Mahdi Dehshiri, Kerlyns Martinez, Lauri Viitasaari
This paper develops a framework for the error analysis in nonparametric model fitting of fractional stochastic differential equations based on discrete observations. We identify an…
Smoothness of martingale observables and generalized Feynman-Kac formulas
Alex Karrila, Lauri Viitasaari
We prove that, under the Hörmander criterion on an Itô process, all its martingale observables are smooth. As a consequence, we also obtain a generalized Feynman-Kac formula provid…
On fractal minimizers and potentials of occupation measures
Michael Hinz, Jonas M. Tölle, Lauri Viitasaari
We consider four prototypes of variational problems and prove the existence of fractal minimizers through the direct method in the calculus of variations. By design these minimizer…
Characterization of continuous stationary fields as generalized Ornstein-Uhlenbeck fields via multi-parameter Langevin equation and multiple Riemann-Stieltjes integration
Marko Voutilainen, Pauliina Ilmonen, Lauri Viitasaari
In this article, we characterize continuous stationary fields via generalized Langevin dynamics. This gives natural connections between stationary fields, stationary increment fiel…
Tanaka formula for SDEs driven by fractional Brownian motion
Tommi Sottinen, Ercan Sönmez, Lauri Viitasaari
We derive a Tanaka-type formula for the solution of a stochastic differential equation (SDE) driven by fractional Brownian motion (fBm) with Hurst parameter . Whil…
Cut-off phenomenon and asymptotic mixing for multivariate general linear processes
Gerardo Barrera, Michael A. Högele, Pauliina Ilmonen +1
The small noise cut-off phenomenon in continuous time and space has been studied in the recent literature for the linear and non-linear stable Langevin dynamics with additive Lévy…
On explosion time in stochastic differential equations driven by fractional Brownian motion
Johanna Garzon, Jorge A. Leon, Soledad Torres +2
In this article, we study the explosion time of the solution to autonomous stochastic differential equations driven by the fractional Brownian motion with Hurst parameter .…
Variability and the existence of rough integrals with irregular coefficients
Michael Hinz, Jonas M. Tölle, Lauri Viitasaari
Within the context of rough path analysis via fractional calculus, we show how variability can be used to prove the existence of integrals with respect to Hölder continuous multipl…
Renormalized stochastic pressure equation with log-correlated Gaussian coefficients
Benny Avelin, Tuomo Kuusi, Patrik Nummi +3
We study periodic solutions to the following divergence-form stochastic partial differential equation with Wick-renormalized gradient on the -dimensional flat torus $\mathbb{T}^…
1D stochastic pressure equation with log-correlated Gaussian coefficients
Benny Avelin, Tuomo Kuusi, Patrik Nummi +3
We study unique solvability for one dimensional stochastic pressure equation with diffusion coefficient given by the Wick exponential of log-correlated Gaussian fields. We prove we…
Transfer principle for fractional Ornstein-Uhlenbeck processes
Tommi Sottinen, Lauri Viitasaari
We prove the transfer principle for fractional Ornstein-Uhlenbeck processes, i.e., we construct a Brownian motion that has the same filtration as the fractional Ornstein-Uhlenbeck…
Discretisation error for stochastic integrals with respect to the fractional Brownian motion with discontinuous integrands and local times
Valentin Garino, Lauri Viitasaari
We consider equidistant Riemann approximations of stochastic integrals with respect to the fractional Brownian motion with , where is an ar…
On Lamperti transformation and characterisations of discrete random fields
Marko Voutilainen, Lauri Viitasaari, Pauliina Ilmonen
In this article we characterise discrete time stationary fields by difference equations involving stationary increment fields and self-similar fields. This gives connections betwee…
On the existence and regularity of local times
Tommi Sottinen, Ercan Sönmez, Lauri Viitasaari
We study the existence and regularity of local times for general -dimensional stochastic processes. We give a general condition for their existence and regularity properties. To…
On sharp rate of convergence for discretisation of integrals driven by fractional Brownian motions and related processes with discontinuous integrands
Ehsan Azmoodeh, Pauliina Ilmonen, Nourhan Shafik +2
We consider equidistant approximations of stochastic integrals driven by Hölder continuous Gaussian processes of order with discontinuous integrands involving bounded v…
Sobolev regularity of occupation measures and paths, variability and compositions
Michael Hinz, Jonas M. Tölle, Lauri Viitasaari
We prove a result on the fractional Sobolev regularity of composition of paths of low fractional Sobolev regularity with functions of bounded variation. The result relies on the no…
Remarks on existence and uniqueness of the solution for stochastic partial differential equations
Benny Avelin, Lauri Viitasaari
In this article we consider existence and uniqueness of the solutions to a large class of stochastic partial differential of form , dri…
Long-range dependent completely correlated mixed fractional Brownian motion
Josephine Dufitinema, Foad Shokrollahi, Tommi Sottinen +1
In this paper we introduce the long-range dependent completely correlated mixed fractional Brownian motion (ccmfBm). This is a process that is driven by a mixture of Brownian motio…
Quantitative normal approximations for the stochastic fractional heat equation
Obayda Assaad, David Nualart, Ciprian A. Tudor +1
In this article we present a {\it quantitative} central limit theorem for the stochastic fractional heat equation driven by a a general Gaussian multiplicative noise, including the…
Local times and sample path properties of the Rosenblatt process
George Kerchev, Ivan Nourdin, Eero Saksman +1
Let be the Rosenblatt process with Hurst index . We prove joint continuity for the local time of , and establish Hölder conditions for the…
Variability of paths and differential equations with -coefficients
Michael Hinz, Jonas M. Tölle, Lauri Viitasaari
We define compositions of Hölder paths in and functions of bounded variation under a relative condition involving the path and the gradient measure of…
Stochastic Differential Equations with Discontinuous Diffusions
Soledad Torres, Lauri Viitasaari
We study one-dimensional stochastic differential equations of form , where is a suitable Hölder continuous driver such as the fractional Brownian motion $B^H…
Oscillating Gaussian Processes
Pauliina Ilmonen, Soledad Torres, Lauri Viitasaari
In this article we introduce and study oscillating Gaussian processes defined by , where are free parameters an…