The (i)Po(m)set Project is a research project at the crossroads of concurrency theory, automata theory, algebra, and geometry. You are at the page of its online seminar.

The seminar is organized by
Uli Fahrenberg,
Christian Johansen
and Krzysztof Ziemiański
and takes place on *zoom*.
If you want to participate,
send an email to ppos-owner@ml.lre.epita.fr
so that we can add you to our mailing list.
You will receive about one email per week in average:
seminar announcements, reminders, and the zoom link.

Talks generally last at most one hour, including time for questions.

See also the seminar's google calendar.

**Michał Gajda**,
Migamake Pte Ltd, Singapore:
**Decomposition of countable semigroups and simplex languages**

Krohn-Rhodes decomposition theorem for finite semigroups facilitates
many other results.
It has been so far generalized to residually finite semigroups.
We use the definition of archimedean semigroups together with
generalization of multiples to propose a further generalization
to decompose any countable semigroups.
We then examine the behaviour of this generalization, by characterizing
languages corresponding to arbitrary countable semigroups,
and proposing a geometric generalization of regular expressions that
provides a useful computable characterization of many such languages.

The work includes a definition of Countable HDA proposed by Krzysztof Ziemiański.

The work includes a definition of Countable HDA proposed by Krzysztof Ziemiański.

**Clovis Eberhart**,
National Institute of Informatics, Tokyo, Japan:
TBA

**Ichiro Hasuo**,
National Institute of Informatics, Tokyo, Japan:
TBA

Workshop on Pomsets and Related Structures (RaPS), Rennes, 24 April 2024.

**Anca Muscholl**,
LaBRI, Université Bordeaux, France:
On partial-order and automata techniques for analysing communication

**Fabio Gadducci**,
Università di Pisa, Italy:
The algebraic view of concatenable net processes

**Paul-André Melliès**,
CNRS, Université Paris Cité, INRIA, France:
The rabbit calculus: convolution products on double categories and categorification of rule algebra

**Henning Basold**,
Universiteit Leiden, The Netherlands:
Towards higher coalgebra: the enriched case

**Uli Fahrenberg**,
LRE, Rennes/Paris, France:
Generating posets with interfaces

**Thomas Kahl**,
Universidade do Minho, Braga, Portugal:
Weak equivalence of higher-dimensional automata

**Mikołaj Bojańczyk**,
University of Warsaw, Poland:
About recognisability of graph languages

**Roman Kniazev**,
IRIF, Paris, France:
Simplicial models for epistemic logic (sprinkled with concurrency)

**Amar Hadzihasanovic**,
TalTech, Tallinn, Estonia:
The homotopy posets of a category

**Rob van Glabbeek**,
University of Edinburgh, Scotland:
Translating Petri nets to higher-dimensional automata

**Łukasz Mikulski**,
NCU, Toruń, Poland:
Relational structures for interval order semantics of concurrent systems

**Matt Earnshaw**,
TalTech, Tallinn, Estonia:
Monoidal languages

**Matteo Acclavio**,
SDU, Odense, Denmark:
The proof theory of pomsets

**Loïc Hélouët**,
IRISA, Rennes, France:
Waiting nets

**Jérémy Dubut-Kross**,
AIST, Tokyo, Japan:
Bisimulations and unfolding in P-accessible categorical models

**Marie Fortin**,
IRIF, Paris, France:
Logics and automata for Message Sequence Charts

**Tobias Kappé**,
Open Universiteit, The Netherlands:
Completeness and the finite model property for Kleene algebra, reconsidered

**Amazigh Amrane**,
EPITA Paris, France:
Series-parallel pomsets: automata and logic

**Sergio Rajsbaum**,
UNAM, Mexico and IRIF, Paris, France:
Unifying concurrent objects and distributed tasks: interval-linearizability

**Safa Zouari**,
NTNU Gjøvik, Norway:
Logical characterization of hh-bisimulation via open maps for HDA