IWC 2020

9th International Workshop on Confluence

30th June 2020, Paris, France

Colocated with FSCD and IJCAR

News

June 15th, 2020: added papers and schedule.
April 7th, 2020: IMPORTANT INFORMATION Due to current travel restrictions in various countries, the meeting will be held virtually this year. The technical details will be given in due time.
December 2019: Created website.

Background

Confluence provides a general notion of determinism and has been conceived as one of the central properties of rewriting systems. Confluence relates to many topics of rewriting (completion, modularity, termination, commutation, etc.) and has been investigated in many formalisms of rewriting, such as first-order rewriting, lambda-calculi, higher-order rewriting, constraint rewriting, conditional rewriting, and so on. Recently there is a renewed interest in confluence research, resulting in new techniques, tool support, confluence competition, and certification as well as in new applications. The scope of the workshop is all these aspects of confluence and related topics.

The goal of the workshop is to provide a forum for researchers interested in the topic of confluence to exchange and share new developments in the field. The workshop will enable discussion on theoretical results, new problems, applications, implementations and benchmarks, and share the current state-of-the-art on the development of confluence tools.

IWC 2020 is part of Paris Nord Summer of LoVe 2020, a joint event on LOgic and VErification at Université Paris 13, made of Petri Nets 2020, IJCAR 2020, FSCD 2020, and over 20 satellite events.

The 9th Confluence Competition CoCo 2020 will run live during IWC 2020.

Topics

confluence and related properties (unique normal forms, commutation, ground confluence)
completion
critical pair criteria
decidability issues
complexity issues
system descriptions
certification
applications of confluence

Important Dates

submission (abstract): Friday, April 17th, 2020
submission (paper): Wednesday, April 22nd, 2020
notification: Friday, May 22nd, 2020
workshop: Tuesday, June 30th, 2020

(deadlines are AoE)

Accepted papers

The proceedings are available online and include reports on the 9th Confluence Competition. You can also find individual papers below:

Vincent van Oostrom. Some symmetries of commutation diamonds
Kiraku Shintani and Nao Hirokawa. Parallel Closedness Revisited
Benjamin Dupont, Philippe Malbos and Cyrille Chenavier. Algebraic critical pair lemma
Ugo De'Liguoro and Riccardo Treglia. On the reduction of the type-free computational Lambda-calculus
Anders Miltner, Kathleen Fisher, Benjamin Pierce, David Walker and Steve Zdancewic. Confluence in Lens Synthesis
Cameron Calk. Coherent Confluence in Modal n-Kleene Algebras
Eelco Visser and Eduardo Amorim. Safety and Completeness of Disambiguation corresponds to Termination and Confluence of Reordering
Jean-Pierre Jouannaud and Fernando Orejas. Confluence of drag rewriting

Program

 9:00-10:00  Frédéric Blanqui: On the use of confluence in type theory modulo rewriting - Invited Talk (slides)
10:00-10:30 Vincent van Oostrom: Some symmetries of commutation diamonds (slides)
10:30-11:00 Kiraku Shintani and Nao Hirokawa: Parallel Closedness Revisited (slides)

11:30-12:00 Benjamin Dupont, Philippe Malbos and Cyrille Chenavier:
Algebraic critical pair lemma  (slides)
12:00-12:30 Ugo De'Liguoro and Riccardo Treglia: On the reduction of the type-free
            computational Lambda-calculus (slides)
12:30-13:00 Anders Miltner, Kathleen Fisher, Benjamin Pierce, David Walker and Steve Zdancewic:
            Confluence in Lens Synthesis (slides)

14:00-15:00 9th Confluence Competition - CoCo 2020 - (slides)
            Report presented by Aart Middeldorp, Kiraku Shintani, Naoki Nishida and Johannes Waldmann
15:00-15:30 Cameron Calk: Coherent Confluence in Modal n-Kleene Algebras (slides)

16:00-17:00  Margherita Zorzi: Compositional theories for embedded programming - Invited Talk  (slides)

17:00-17:30 Eelco Visser and Eduardo Amorim: Safety and Completeness of Disambiguation corresponds
            to Termination and Confluence of Reordering (slides)
17:30-18:00 Jean-Pierre Jouannaud and Fernando Orejas: Confluence of drag rewriting  (slides)
18:00-18:05 Closing and Announcement of the IWC SC by Takahito Aoto (slides)

Some screen shots: sc01 sc02 sc03 sc04 sc05 sc06 sc07 sc08 sc09 sc10 sc11 sc12

Unedited Live Broadcast

Invited Speakers

Margherita Zorzi (Università degli Studi di Verona) Compositional theories for embedded programming
Abstract: Embedded programming style allows to split the syntax in two parts, representing respectively a host language H and a core language C embedded in H. This formally models several situations in which a user writes code in a main language and delegates some tasks to an ad hoc domain specific language. Moreover, as showed in recent years, a particular case of the host-core approach allows a flexible management of data linearity, which is particularly useful in non-classical computational paradigms such as quantum computing. The definition of a systematised type theory to capture and standardize common properties of embedded languages is partially unexplored. We present a flexible fragment of such a type theory, together with its semantics in terms of enriched categories. We introduce the calculus HC0 and we use the notion of internal language of a category to relate the language to the class of its models, showing the equivalence between the category of models and the one of theories. This provides a stronger result w.r.t. standard soundness and completeness since it involves not only the models but also morphisms between models. We observe that the definition of the morphisms between models highlights further advantages of the embedded languages and we discuss some concrete instances, extensions and specializations of the syntax and the semantics.
Frédéric Blanqui (INRIA LSV ENS Paris - Saclay/Université Saclay) "On the use of confluence in type theory modulo rewriting"
Abstract: Various proof assistants advocate the use of rewriting in type theory, especially Dedukti. This however raises a number of problems. In this talk, I will present various properties of type theory modulo.

Program Committee

Beniamino Accattoli (INRIA & LIX, École Polytechnique)
Mauricio Ayala-Rincón (Universidade de Brasília), co-chair
Cyrille Chenavier (Centre Inria Lille)
Alejandro Díaz-Caro (Universidad Nacional de Quilmes & ICC/UBA-CONICET)
Maribel Fernández (King's College London)
Mario Florido (Universidade de Porto)
Makoto Hamana (Gunma University)
Philippe Malbos (Université Claude Bernard Lyon 1)
Samuel Mimram (LIX, École Polytechnique), co-chair
Camilo Rocha (Pontificia Universidad Javeriana - Cali)
Daniel Lima Ventura (Universidade Federal de Goiás)
Femke van Raamsdonk (VU University Amsterdam)
Johannes Waldmann (Hochschule für Technik, Wirtschaft und Kultur Leipzig)
Sarah Winkler (Università degli studi di Verona)

IWC Steering Committee

Previous IWCs

1st IWC, Nagoya, 2012
2nd IWC, Eindhoven, 2013
3rd IWC, Vienna, 2014
4th IWC, Berlin, 2015
5th IWC, Obergurgl, 2016
6th IWC, Oxford, 2017
7th IWC, Oxford, 2018
9th IWC, Dortmund, 2019

Contact

Mauricio Ayala-Rincón: ayala(at)unb.br
Samuel Mimram: samuel.mimram(at)lix.polytechnique.fr