Post-groups,(Lie-) Butcher groups and the Yang–Baxter equation

C Bai, L Guo, Y Sheng, R Tang - Mathematische Annalen, 2024 - Springer
The notions of a post-group and a pre-group are introduced as a unification and enrichment
of several group structures appearing in diverse areas from numerical integration to the …

A diagram-free approach to the stochastic estimates in regularity structures

P Linares, F Otto, M Tempelmayr, P Tsatsoulis - Inventiones mathematicae, 2024 - Springer
In this paper, we explore the version of Hairer's regularity structures based on a greedier
index set than trees, as introduced in (Otto et al. in A priori bounds for quasi-linear SPDEs in …

A top-down approach to algebraic renormalization in regularity structures based on multi-indices

Y Bruned, P Linares - Archive for Rational Mechanics and Analysis, 2024 - Springer
We provide an algebraic framework to describe renormalization in regularity structures
based on multi-indices for a large class of semi-linear stochastic PDEs. This framework is …

The structure group for quasi-linear equations via universal enveloping algebras

P Linares, F Otto, M Tempelmayr - Communications of the American …, 2023 - ams.org
We replace trees by multi-indices as an index set of the abstract model space to tackle quasi-
linear singular stochastic partial differential equations. We show that this approach is …

Novikov algebras and multi-indices in regularity structures

Y Bruned, V Dotsenko - arXiv preprint arXiv:2311.09091, 2023 - arxiv.org
In this work, we introduce multi-Novikov algebras, a generalisation of Novikov algebras with
several binary operations indexed by a given set, and show that the multi-indices recently …

Post-Lie algebras of derivations and regularity structures

JD Jacques, L Zambotti - arXiv preprint arXiv:2306.02484, 2023 - arxiv.org
Given a commutative algebra $ A $, we exhibit a canonical structure of post-Lie algebra on
the space $ A\otimes Der (A) $ where $ Der (A) $ is the space of derivations on $ A $, in …

Post-Hopf algebras, relative Rota–Baxter operators and solutions to the Yang–Baxter equation

Y Li, Y Sheng, R Tang - Journal of Noncommutative Geometry, 2023 - ems.press
In this paper, first, we introduce the notion of post-Hopf algebra, which gives rise to a post-
Lie algebra on the space of primitive elements and the fact that there is naturally a post-Hopf …

Multi‐indice BB‐series

Y Bruned, K Ebrahimi‐Fard… - Journal of the London …, 2025 - Wiley Online Library
We propose a novel way to study numerical methods for ordinary differential equations in
one dimension via the notion of multi‐indice. The main idea is to replace rooted trees in …

Lecture notes on Malliavin calculus in regularity structures

L Broux, F Otto, M Tempelmayr - arXiv preprint arXiv:2401.05935, 2024 - arxiv.org
Malliavin calculus provides a characterization of the centered model in regularity structures
that is stable under removing the small-scale cut-off. In conjunction with a spectral gap …

Composition and substitution of Regularity Structures B-series

Y Bruned - arXiv preprint arXiv:2310.14242, 2023 - arxiv.org
In this work, we introduce Regularity Structures B-series which are used for describing
solutions of singular stochastic partial differential equations (SPDEs). We define composition …