Isa Vialard

I am a postdoctoral researcher at MPI-SWS, where I am part of the Foundations of Algorithmic Verification group led by Joël Ouaknine. I am currently working on weighted timed games. Before that, I did my PhD at Laboratoire Méthodes Formelles, ENS Paris Saclay, under the supervision of Philippe Schnoebelen.

My PhD Thesis: Measuring well quasi-orders and complexity of verification.

Contact

You can contact me at surname[at]mpi-sws[dot]org

Research interests

My main interests are well quasi-orders, their ordinal measures, with application to the verification of well-structured transition systems. Recently I have started working on weighted timed games. I am also interested in proof assistants and combinatorics on words.

Publications

Journal articles

• I. Vialard, On the Width of the Cartesian Product of Ordinals, Order, vol 42, pp. 37-58 (2024).

• Ph. Schnoebelen and I. Vialard, On the piecewise complexity of words, Acta Informatica, vol 62 (2025).

• I. Vialard, On maximal order type of the lexicographic product, Logic journal of the IGPL.

Conference proceedings

• M. Praveen, Ph. Schnoebelen, I. Vialard, J. Veron, On the piecewise complexity of words and periodic words, SOFSEM, LNCS, pp 456-470 (2024)

• I. Vialard, Ordinal Measures of the Set of Finite Multisets, MFCS 2023.

• Ph. Schnoebelen, M. Veron, I. Vialard, A Tropical Approach to the Compositional Piecewise Complexity of Words and Compressed Words, ICALP 2025.

In preparation

• S. Abriola, S. Halfon, A. Lopez, S. Schmitz, Ph. Schnoebelen, I. Vialard, Measuring well quasi-ordered finitary powersets, submitted for publication.

• Q. Guilmant, J. Ouaknine, I. Vialard, The Value Problem for Weighted Timed Games with Two Clocks is Undecidable, submitted for publication.

• I. Vialard, Deciding the Value of Two-Clock Almost Non-Zeno Weighted Timed Games, submitted for publication.

• R. Aghamov, C. Baier, J. Ouaknine, J. Piribauer, M. Vahanwala, I. Vialard, Temporal Properties of Conditional Independence in Dynamic Bayesian Networks, submitted for publication.

Presentations in conferences, workshops, seminars

• Tropical algebra for piecewise complexity, ICALP, Aarhus, July 2025.

• Tropical algebra for piecewise complexity, workshop “Words and Subwords”, Liège, April 2025.

• Journées annuelles du GT Verif, Lille, Novembre 2024.

• Séminaire LX du LaBRI, Bordeaux, Novembre 2024.

• Séminaire automate de l’IRIF, Paris, Octobre 2024.

• My PhD defense, Measuring well quasi-orders and complexity of verification, ENS Paris-Saclay, July 2024.

• Journées annuelles du GT Verif, Paris, Novembre 2023.

• Ordinal measures of the set of finite multisets, MFCS, Bordeaux, September 2023.

• Séminaire à Liverpool University, July 2023.

• Elementary, Dr. Powerset!, workshop “WQO-BQO - what is up?”, Lyon, March 2023. (This is the sequel to a talk given by Aliaume Lopez at the same workshop.)

• Research school “Discrete mathematics and logic”, Marseille, January 2023.

• Highlights, Paris, June 2022.

Teaching and supervision

• May-August 2025: I am supervising Angel Wuttke for his internship on the topic of 2-clock almost strongly non-Zeno weighted timed games.

• 2021-2024: I taught Formal languages, Rewriting theory, Architecture and systems, and Logic Project (an introduction to proof assistants) at ENS Paris-Saclay.

Miscellaneous

• I have a ha-index of 64.
• My favourite time-sink : Rätsel Portal