Working group

Manage talks

Graphs and Logic


Day, hour and place

Wednesday at 1:30pm, room 3052

The calendar of events (iCal format).
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Contact(s)

Hector Buffiere
Giannos Stamoulis

This working group aims to exchange and collaborate around problems linking model theory and structural graph theory.

It is structured around a monthly seminar of two presentations and weekly working meetings on research questions.


Next talk

Graphs and Logic
Wednesday April 30, 2025, 1:30PM, Salle 1021
Sylvain Schmitz (IRIF) Well quasi-orders and preservation theorems for First-Order Logic - Part II

Continuation of part I. I intend to cover
  1. applications of WQOs in algorithmic graph theory,
  2. a focus on classes of graphs that are well-quasi-ordered by the induced subgraph ordering, along with Pouzet’s Conjecture,
  3. the generalisation to preservation properties in first-order logic.


Previous talks


Year 2025

Graphs and Logic
Wednesday March 26, 2025, 1:30PM, salle 3052
Sylvain Schmitz; Giannos Stamoulis Well quasi-orders and preservation theorems for First-Order Logic; Some extensions of First-Order logic on graphs

This will be a gentle tutorial on mostly standard results about well-quasi-orders (wqo) in a context of graph theory and algorithmic meta-theorems. I intend to cover a few basics of wqo theory, their applications in algorithmic graph theory, a focus on classes of graphs that are well-quasi-ordered by the induced subgraph ordering, along with Pouzet's Conjecture, and finally the generalisation to preservation properties in first-order logic.

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In this tutorial we present a landscape of extensions of first-order logic (on graphs) and we discuss their expressive power and algorithmic results related to them. These extensions involve either additional predicates expressing different types of connectivity or the quantification over vertex sets that are (in a sense) of simple structure.