Quatre-vingts: Workshop on Constructive Mathematics
Dedicated to Douglas Bridges and Henri Lombardi

10-12 September 2026, Paris

Program (in progress)

Mariemi Alonso García: TBA
Andrej Bauer: TBA (online)
Thierry Coquand: TBA
André Galligo: Polynomial roots set collective motion under differentiation
Hajime Ishihara: Basic pairs and uniformities
Peter LeFanu Lumsdaine: Makkai’s lost projectivity result
Maria Emilia Maietti: Reconciling Both Classical and Intuitionistic Mathematics with Russian Constructivism
Ralph Matthes: Understanding simultaneous collapse in the dynamical method through natural deduction
Stefan Neuwirth: L'épistémologie mathématique d’Henri Lombardi
Iosif Petrakis: On the mathematical work of Douglas Bridges
Jan von Plato: Gödel's remarks on Bishop's constructive mathematics
Michael Rathjen: Omniscience Principles as Ideal Characters (online)
Giovanni Sambin: Positive Topology and Dynamic Constructivism: Prospects for the Future
Helmut Schwichtenberg: Type Theory with Partial Objects
Claire Tête: TBA
Franziskus Wiesnet: On the Limits of Recursive Characterizations in the Refined A-Translation
Ihsen Yengui: Algorithms for computing syzygies over V[X1, ... , Xn], V a valuation domain

Location

The workshop will be held in a former flour-market building of University Paris Cité called “Halles aux Farines”, 8 esplanade Pierre Vidal-Naquet, Paris (this is in the 13th arrondissement, in the extreme south-east corner of Paris, a lively modern mixed student-residential-tertiary area accessible with subway line 14, RER C, tramway T3a and buses 25, 62, 64, 89, 325).

There are plenty of hotels, in Paris as well as in the first suburb belt nearby, typically in Ivry-sur-Seine or Charenton-le-Pont.

The closest one (200m away) is Appart'City Paris Grande Bibliothèque.

Nearby (400m away horizontally and 130m vertically), there is also the panoramic (but expensive) TOO Hotel.

Not so far, in a quiet street (1km away), there is Hotel Richemont which visitors of the university say to appreciate.

Not so far (1km away), in a modern area, there is the Résidhome Quai d'Ivry as well as the B&B Hotel Paris Ivry Quai de Seine.

Across the Seine, there is (1km away) Ibis Paris Bercy Village, in a lively modern going-out place built around an old Wine market.

For more central Paris locations, you can consider the 5th arrondissement, connected via bus 89 and RER C, or Place d'Italie, Butte aux Cailles, Gobelins, ..., more at the center of the 13rd arrondissement, connected via bus 62 and 64.

Registration

Registration is mandatory but free.

Organisation