Florent Koechlin's personal webpage 🇫🇷 🇬🇧

Florent Koechlin
CNRS researcher
Office Y309
Bâtiment Hypatia
Laboratoire d'Informatique de Paris Nord
99, avenue Jean-Baptiste Clément
93430 Villetaneuse
florent.koechlin(at)lipn.fr

Presentation

Research Interests

I am a research associate in the CALIN team since October, 2023. My research interests include analytic combinatorics, automata theory, combinatorial geometry, and algorithm analysis.

Working groups, and projects

• I am part of the ANR Diplo and the ANR COMETA-GAE.
• I also organize at LIPN a reading group about D-finite functions. The idea of this group is to learn recent tools on D-finite functions developed in computer algebra, particularly around creative telescoping.

Scientific event organization, seminars, and editorial responsibilities

• I am co-responsible with Meltem Ünel of the CALIN seminar.
• I am a managing editor of the journal European Journal of Combinatorics.
• I co-organized the ALEA Days 2026.

Publications

Conferences

• Florent Koechlin, Carine Pivoteau, Pablo Rotondo. Heuristic universality detection over regular expressions specified by systems. DLT'25 -- slides
• Mathilde Bouvel, Valentin Feray, Xavier Goaoc, and Florent Koechlin. A Canonical Tree Decomposition for Chirotopes. SoCG'24 -- slides
• Arnaud Carayol, Philippe Duchon, Florent Koechlin and Cyril Nicaud. One Drop of Non-Determinism in a Random Deterministic Automaton. STACS'23 -- slides
• Florent Koechlin. New analytic techniques for proving the inherent ambiguity of context-free languages. FSTTCS'22
• Florent Koechlin and Pablo Rotondo. Analysis of an efficient reduction algorithm for random regular expressions based on universality detection. CSR'21
• Florent Koechlin and Pablo Rotondo. Absorbing patterns in BST-like expression-trees. STACS'21
• Alin Bostan, Arnaud Carayol, Florent Koechlin and Cyril Nicaud. Weakly-unambiguous Parikh automata and their link to holonomic series. ICALP'20, pages 114:1-114:16.
• Florent Koechlin, Cyril Nicaud and Pablo Rotondo. On the Degeneracy of Random Expressions Specified by Systems of Combinatorial Equations. DLT'20
• Florent Koechlin, Cyril Nicaud and Pablo Rotondo. Uniform Random Expressions Lack Expressivity. MFCS'19 (14 p.)

Journals

• Mathilde Bouvel, Valentin Féray, Xavier Goaoc, Florent Koechlin. A canonical tree decomposition for order types, and some applications. SIAM Journal on Discrete Mathematics, 2025, 39 (4), pp.2189-2241.
• Arnaud Carayol, Philippe Duchon, Florent Koechlin, Cyril Nicaud. Random Deterministic Automata With One Added Transition. Log. Methods Comput. Sci. 21(1) (2025)
• Florent Koechlin, Cyril Nicaud and Pablo Rotondo. Simplifications of Uniform Expressions Specified by Systems. IJFCS'21, Volume No. 32, Issue No. 06, pp. 733 - 760.

Analysis of Algorithms (MPRI)

See the page dedicated to the course. The password is indicated on the page.

Before Recruitment

Career Path

• 01/10/2023-actuel: CNRS researcher at CNRS
• 01/02/2022-30/09/2023 : Postdoctoral researcher at LORIA
• 01/09/21-31/01/22 : ATER at Irif
• 2018-2021 : PhD student in Computer Science

PhD

I carried out my PhD at LIGM, at Gustave Eiffel University (formerly Paris-Est Marne-la-Vallée University), under the supervision of Arnaud Carayol and Cyril Nicaud.
My thesis is titled Systems of holonomic functions: Application to Automata Theory.

I defended my thesis on December 9th, 2021.
Thesis Manuscript (last revised on March 9, 2022)