This is the homepage of the ESSLLI 2026 workshop whose aim is to bring together researchers who apply semantic approaches in the study of expressiveness and complexity problems in logic. In particular, the objective is to provide a platform for researchers who apply tools from

in the algorithm-oriented fields of theoretical computer science, such as

Examples include the use of category theory in automata theory, formal language theory, in the study of graph invariants, and dynamic programming algorithms. Similarly relevant are applications of algebra and topology in CSP, or applications of duality theory and topology in finite model theory and quantum isomorphisms.

Dates

Invited Lectures

Submitting instructions

Apart from invited lectures there will be a number of contributed talks. If you are interested in giving a talk, please write to tomas.jakl@cvut.cz with a title of your talk and a short abstract (1-2 paragraphs).

Although the deadline for submission is 30 April 2026, please feel free to write earlier, to express the intent to submit.

Preliminary schedule

Monday Tuesday Wednesday Thursday Friday
Session 1 Introductory Lecture Introductory Lecture Introductory Lecture 2 talks 2 talks
Session 2 2 talks 2 talks Problem Session 2 talks Problem Session
Evening Workshop Dinner

Moreover, the participants are encouraged to also take part in the rest of the ESSLLI programme.

Similar events

Since 2020, the community around the algebraic approach to CSP has met yearly at the so-called CSP World Congress. The categorical approach to automata theory and formal languages concentrates around the Conference on Algebra and Coalgebra in Computer Science (CALCO), held every odd year since 2005, and the Workshop on Coalgebraic Methods in Computer Science (CMCS), held every even year. Also, in 2025, there was a Dagstuhl workshop called Categories for Automata and Language Theory aimed at the same community.

However, our scope is wider than these events. It follows the tradition of the one- and two-day Structure meets Power series of workshops, see 2026, 2024, 2023, 2022, 2021. Unlike with the Structure meets Power workshop, which are typically short, this workshop is a dedicated multi-day workshop designed to provide more space for interaction.

Organisers