Lasse Leskelä

Professori (Associate professor)
Professori (Associate professor)
T302 Dept. Mathematics and Systems Analysis

My research area is stochastics, the mathematical theory of random events, systems, and processes. The main focus is statistical network models and random graphs, together with random dynamical systems and stochastic processes acting on networks. The general objective is to derive fundamental mathematical laws for predicting the macroscopic behavior of large random systems and describing the accuracy of statistical learning algorithms for large network models. Such laws allow to make predictions using massive high-dimensional data sets for which classical methods of statistics and machine learning are often infeasible. Statistical network models under study include random intersection graphs, stochastic block models, and graphons. The archetypes of stochastic dynamics studied are branching processes, random walks, and first passage percolation. The formulas and methods have a wide range of applications ranging from information and social networks to biological and financial systems.

Full researcher profile


Probability theory, Stochastic processes, Random graphs, Statistical network models, Queueing Theory, Applied probability, Stochastics, Stochastic modeling, 112 Statistics and probability, Applied mathematics


Varma-Sampo MSc thesis prize, Finnish Mathematical Society

Award or honor granted for a specific work Department of Mathematics and Systems Analysis Jan 2000

McKinsey Prize

McKinsey Prize for the best MSc degree completed in 1999 at the Helsinki University of Technology.
Award or honor granted for academic or artistic career Department of Mathematics and Systems Analysis Jan 2000


  • Statistics and Mathematical Data Science, Professor (Associate Professor)


Recovering Static and Time-Varying Communities Using Persistent Edges

Konstantin Avrachenkov, Maximilien Dreveton, Lasse Leskela 2024

Distinguishing subsampled power laws from other heavy-tailed distributions

Silja Sormunen, Lasse Leskelä, Jari Saramäki 2024

Multilayer Hypergraph Clustering Using the Aggregate Similarity Matrix

Kalle Alaluusua, Konstantin Avrachenkov, B. R.Vinay Kumar, Lasse Leskelä 2023 Algorithms and Models for the Web Graph - 18th International Workshop, WAW 2023, Proceedings

Tilastotieteen sanasto : verkkoversio (2023)

Juha Alho, Elja Arjas, Juha Karvanen, Lasse Leskelä, Esa Läärä, Pekka Pere 2023

Persistence in a large network of sparsely interacting neurons

Maximiliano Altamirano, Roberto Cortez, Matthieu Jonckheere, Lasse Leskelä 2023

Estimating inter-regional mobility during disruption: Comparing and combining different data sources

Sara Heydari, Zhiren Huang, Takayuki Hiraoka, Alejandro Ponce de Leon Chavez, Tapio Ala-Nissila, Lasse Leskelä, Mikko Kivelä, Jari Saramäki 2023