One World Seminar Series on the

Mathematics of Machine Learning

The One World Seminar Series on the Mathematics of Machine Learning is an online platform for research seminars, workshops and seasonal schools in theoretical machine learning. The focus of the series lies on theoretical advances in machine learning and deep learning as a complement to the one world seminars on probability, on Information, Signals and Data (MINDS), on methods for arbitrary data sources (MADS), and on imaging and inverse problems (IMAGINE).

The series was started during the Covid-19 epidemic in 2020 to bring together researchers from all over the world for presentations and discussions in a virtual environment. It follows in the footsteps of other community projects under the One World Umbrella which originated around the same time.

We welcome suggestions for speakers concerning new and exciting developments and are committed to providing a platform also for junior researchers. We recognize the advantages that online seminars provide in terms of flexibility, and we are experimenting with different formats. Any feedback on different events is welcome.

Next Event

Wed Sept 28

No Seminar, SIAM MDS22

Wed Oct 5
12 noon ET

On the Resolution of a Theoretical Question Related to the Nature of Local Training in Federated Learning

We study distributed optimization methods based on the local training (LT) paradigm - achieving improved communication efficiency by performing richer local gradient-based training on the clients before parameter averaging - which is of key importance in federated learning. Looking back at the progress of the field in the last decade, we identify 5 generations of LT methods: 1) heuristic, 2) homogeneous, 3) sublinear, 4) linear, and 5) accelerated. The 5th generation, initiated by the ProxSkip method of Mishchenko et al (2022) and its analysis, is characterized by the first theoretical confirmation that LT is a communication acceleration mechanism. In this talk, I will explain the problem, its solution, and some subsequent work generalizing, extending and improving the ProxSkip method in various ways.


1. Konstantin Mishchenko, Grigory Malinovsky, Sebastian Stich and Peter Richtárik. ProxSkip: Yes! Local gradient steps provably lead to communication acceleration! Finally! Proceedings of the 39th International Conference on Machine Learning, 2022

2. Grigory Malinovsky, Kai Yi and Peter Richtárik. Variance reduced ProxSkip: Algorithm, theory and application to federated learning, arXiv:2207.04338, 2022

3. Laurent Condat and Peter Richtárik. RandProx: Primal-dual optimization algorithms with randomized proximal updates, arXiv:2207.12891, 2022

4. Abdurakhmon Sadiev, Dmitry Kovalev and Peter Richtárik. Communication acceleration of local gradient methods via an accelerated primal-dual algorithm with inexact prox, arXiv:2207.03957, 2022

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Seminars are held online on Zoom. The presentations are recorded and video is made available on our youtube channel. A list of past seminars can be found here. All seminars, unless otherwise stated, are held on Wednesdays at 12 noon ET. The invitation will be shared on this site before the talk and distributed via email.


Wuyang Chen (UT Austin)

Boumediene Hamzi (Caltech)

Franca Hoffmann (University of Bonn)

Issa Karambal (Quantum Leap Africa)

Philipp Petersen (University of Vienna)

Matthew Thorpe (University of Manchester)

Tiffany Vlaar (University of Edinburgh)

Stephan Wojtowytsch (Texas A&M)

Former Board Members

Simon Shaolei Du (University of Washington)

Surbhi Goel (Microsoft Research NY)

Chao Ma (Stanford University)

Song Mei (UC Berkeley)