POPL 2024
Sun 14 - Sat 20 January 2024 London, United Kingdom

Certified Programs and Proofs (CPP) is an international conference on practical and theoretical topics in all areas that consider formal verification and certification as an essential paradigm for their work. CPP spans areas of computer science, mathematics, logic, and education. CPP is sponsored by ACM SIGPLAN, in cooperation with ACM SIGLOG.

CPP 2024 will be held on 15-16 January 2024 and will be co-located with POPL 2024 in London, UK.

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Dates
Plenary
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Mon 15 Jan

Displayed time zone: London change

09:00 - 10:30
Logic and BeyondCPP at Kelvin Lecture
Chair(s): Sandrine Blazy University of Rennes
09:00
60m
Keynote
Under-approximation for Scalable Bug Detection
CPP
Azalea Raad Imperial College London
10:00
30m
Talk
A mechanised and constructive reverse analysis of soundness and completeness of bi-intuitionistic logic
CPP
Ian Shillito Australian National University, Dominik Kirst Ben-Gurion University of the Negev
Pre-print
10:30 - 11:00
10:30
30m
Coffee break
Break
Catering

11:00 - 12:30
Compiler / Program VerificationCPP at Kelvin Lecture
Chair(s): Vadim Zaliva University of Cambridge, UK
11:00
30m
Talk
The Last Yard: Foundational End-to-End Verification of High-Speed Cryptography
CPP
Philipp G. Haselwarter Aarhus University, Benjamin Salling Hvass Aarhus University, Lasse Letager Hansen Aarhus University, Theo Winterhalter INRIA Saclay, Cătălin Hriţcu MPI-SP, Bas Spitters Aarhus University
Pre-print File Attached
11:30
30m
Talk
UTC time, formally verified
CPP
Ana de Almeida Borges University of Barcelona and Formal Vindications S.L., Mireia González Bedmar University of Barcelona and Formal Vindications S.L., Juan Conejero Rodríguez University of Barcelona and Formal Vindications S.L., Eduardo Hermo Reyes University of Barcelona and Formal Vindications S.L., Joaquim Casals Buñuel University of Barcelona and Formal Vindications S.L., Joost J. Joosten University of Barcelona
12:00
30m
Talk
VCFloat2: Floating-point error analysis in Coq
CPP
Andrew W. Appel Princeton University, Ariel E. Kellison Cornell University
Pre-print
12:30 - 14:00
12:30
90m
Lunch
Lunch
Catering

14:00 - 15:30
Isabelle, PVSCPP at Kelvin Lecture
Chair(s): Dmitriy Traytel University of Copenhagen
14:00
30m
Talk
A Temporal Differential Dynamic Logic Formal Embeddingremote presentation
CPP
Lauren White NASA, Laura Titolo AMA/NASA LaRC, J Tanner Slagel NASA, Cesar Munoz NASA
14:30
30m
Talk
Formal Probabilistic Methods for Combinatorial Structures using the Lovász Local Lemmadistinguished paper
CPP
Chelsea Edmonds University of Sheffield, Lawrence Paulson University of Cambridge
Pre-print
15:00
30m
Talk
Certification of Confluence- and Commutation-Proofs via Parallel Critical Pairs
CPP
Nao Hirokawa Japan Advanced Institute of Science and Technology, Dohan Kim University of Innsbruck, Kiraku Shintani Japan Advanced Institute of Science and Technology, René Thiemann University of Innsbruck
15:30 - 16:00
15:30
30m
Coffee break
Break
Catering

16:00 - 17:30
Formalizing MathematicsCPP at Kelvin Lecture
Chair(s): Kuen-Bang Hou (Favonia) University of Minnesota
16:00
30m
Talk
A Formalization of Complete Discrete Valuation Rings and Local Fields
CPP
María Inés de Frutos-Fernández Universidad Autónoma de Madrid, Filippo Alberto Edoardo Nuccio Mortarino Majno di Capriglio Université Jean Monnet Saint-Étienne
Pre-print
16:30
30m
Talk
Formalizing Giles Gardam's Disproof of Kaplansky's Unit Conjecture
CPP
Siddhartha Gadgil Indian Institute of Science, Anand Rao Tadipatri Indian Institute of Science Education and Research
17:00
30m
Talk
Strictly Monotone Brouwer Trees for Well Founded Recursion Over Multiple Argumentsremote presentation
CPP
Joseph Eremondi University of Regina
Pre-print
17:35 - 18:30
Business MeetingCPP at Kelvin Lecture
17:35
55m
Meeting
Business Meeting
CPP
Amin Timany Aarhus University, Dmitriy Traytel University of Copenhagen

Tue 16 Jan

Displayed time zone: London change

09:00 - 10:30
Interactive Proof Development CPP at Kelvin Lecture
Chair(s): Brigitte Pientka McGill University
09:00
60m
Keynote
Improved Assistance for Interactive Proof
CPP
Cezary Kaliszyk University of Innsbruck
10:00
30m
Talk
Martin-Löf à la Coqdistinguished paper
CPP
Arthur Adjedj ENS Paris Saclay, Université Paris-Saclay, Meven Lennon-Bertrand University of Cambridge, Kenji Maillard INRIA, Pierre-Marie Pédrot INRIA, Loïc Pujet Stockholm University
10:30 - 11:00
10:30 - 11:00
10:30
30m
Coffee break
Break
Catering

11:00 - 12:30
Formalizations of Category TheoryCPP at Kelvin Lecture
Chair(s): Robert Atkey University of Strathclyde
11:00
30m
Talk
Displayed Monoidal Categories for the Semantics of Linear Logic
CPP
Benedikt Ahrens Delft University of Technology, Ralph Matthes IRIT, Université de Toulouse, CNRS, Toulouse INP, UT3, Toulouse, Niels van der Weide Radboud University, Kobe Wullaert Delft University of Technology
11:30
30m
Talk
Univalent Double Categories
CPP
Niels van der Weide Radboud University, Nima Rasekh Max Planck Institute for Mathematics, Benedikt Ahrens Delft University of Technology, Paige Randall North Utrecht University
12:00
30m
Talk
Formalizing the ∞-categorical Yoneda lemma
CPP
Nikolai Kudasov Innopolis University, Emily Riehl Johns Hopkins University, Jonathan Weinberger Johns Hopkins University
Link to publication DOI Pre-print
12:30 - 14:00
12:30
90m
Lunch
Lunch
Catering

12:30 - 14:00
12:30
90m
Lunch
Lunch
Catering

14:00 - 15:30
Mechanized separation logicCPP at Kelvin Lecture
Chair(s): Amin Timany Aarhus University
14:00
30m
Talk
Compositional Verification of Concurrent C Programs with Search Structure Templates
CPP
Duc-Than Nguyen University of Illinois at Chicago, Lennart Beringer Princeton University, William Mansky University of Illinois Chicago, Shengyi Wang Princeton University, USA
Pre-print
14:30
30m
Talk
Rooting for Efficiency: Mechanised Reasoning about Array-Based Trees in Separation Logicdistinguished paper
CPP
Qiyuan Zhao National University of Singapore, George Pîrlea National University of Singapore, Zhendong Ang National University of Singapore, Umang Mathur National University of Singapore, Ilya Sergey National University of Singapore
Pre-print
15:00
30m
Talk
Unification for Subformula Linking under Quantifiers
CPP
Ike Mulder Radboud University Nijmegen, Robbert Krebbers Radboud University Nijmegen
Pre-print
15:30 - 16:00
15:30
30m
Coffee break
Break
Catering

15:30 - 16:00
15:30
30m
Coffee break
Break
Catering

16:00 - 17:30
Verified CompilationCPP at Kelvin Lecture
Chair(s): Arthur Charguéraud Inria
16:00
30m
Talk
Lean Formalization of Extended Regular Expression Matching with Lookarounds
CPP
Ekaterina Zhuchko Tallinn University of Technology, Margus Veanes Microsoft Research, Gabriel Ebner Microsoft Research
16:30
30m
Talk
Memory simulations, security and optimization in a verified compiler
CPP
David Monniaux Université Grenoble Alpes - CNRS - Grenoble INP - Verimag
17:00
30m
Talk
PfComp: A Verified Compiler for Packet Filtering Leveraging Binary Decision Diagrams
CPP

Accepted Papers

Title
A Formalization of Complete Discrete Valuation Rings and Local Fields
CPP
Pre-print
A mechanised and constructive reverse analysis of soundness and completeness of bi-intuitionistic logic
CPP
Pre-print
A Temporal Differential Dynamic Logic Formal Embeddingremote presentation
CPP
Certification of Confluence- and Commutation-Proofs via Parallel Critical Pairs
CPP
Compositional Verification of Concurrent C Programs with Search Structure Templates
CPP
Pre-print
Displayed Monoidal Categories for the Semantics of Linear Logic
CPP
Formalizing Giles Gardam's Disproof of Kaplansky's Unit Conjecture
CPP
Formalizing the ∞-categorical Yoneda lemma
CPP
Link to publication DOI Pre-print
Formal Probabilistic Methods for Combinatorial Structures using the Lovász Local Lemmadistinguished paper
CPP
Pre-print
Improved Assistance for Interactive Proof
CPP
Lean Formalization of Extended Regular Expression Matching with Lookarounds
CPP
Martin-Löf à la Coqdistinguished paper
CPP
Memory simulations, security and optimization in a verified compiler
CPP
PfComp: A Verified Compiler for Packet Filtering Leveraging Binary Decision Diagrams
CPP
Rooting for Efficiency: Mechanised Reasoning about Array-Based Trees in Separation Logicdistinguished paper
CPP
Pre-print
Strictly Monotone Brouwer Trees for Well Founded Recursion Over Multiple Argumentsremote presentation
CPP
Pre-print
The Last Yard: Foundational End-to-End Verification of High-Speed Cryptography
CPP
Pre-print File Attached
Under-approximation for Scalable Bug Detection
CPP
Unification for Subformula Linking under Quantifiers
CPP
Pre-print
Univalent Double Categories
CPP
UTC time, formally verified
CPP
VCFloat2: Floating-point error analysis in Coq
CPP
Pre-print

Call for Papers

Certified Programs and Proofs (CPP) is an international conference on practical and theoretical topics in all areas that consider formal verification and certification as an essential paradigm for their work. CPP spans areas of computer science, mathematics, logic, and education.

CPP 2024 (https://popl24.sigplan.org/home/CPP-2024) will be held on 15-16 January 2024 and will be co-located with POPL 2024 in London, UK. CPP 2024 is sponsored by ACM SIGPLAN, in cooperation with ACM SIGLOG.

CPP 2024 will welcome contributions from all members of the community. The CPP 2024 organizers will strive to enable both in-person and remote participation, in cooperation with the POPL 2024 organizers.

IMPORTANT DATES

  • Abstract Submission Deadline: 12 September 2023 at 23:59 AoE (UTC-12h)
  • Paper Submission Deadline: 19 September 2023 at 23:59 AoE (UTC-12h)
  • Notification (tentative): 21 November 2023
  • Camera Ready Deadline (tentative): TBA
  • Conference: 15-16 January 2023

Deadlines expire at the end of the day, anywhere on earth. Abstract and submission deadlines are strict and there will be no extensions.

DISTINGUISHED PAPER AWARDS

Around 10% of the accepted papers at CPP 2023 will be designated as Distinguished Papers. This award highlights papers that the CPP program committee thinks should be read by a broad audience due to their relevance, originality, significance and clarity.

TOPICS OF INTEREST

We welcome submissions in research areas related to formal certification of programs and proofs. The following is a non-exhaustive list of topics of interest to CPP:

  • certified or certifying programming, compilation, linking, OS kernels, runtime systems, security monitors, and hardware;
  • certified mathematical libraries and mathematical theorems;
  • proof assistants (e.g, ACL2, Agda, Coq, Dafny, F*, HOL4, HOL Light, Idris, Isabelle, Lean, Mizar, Nuprl, PVS, etc);
  • new languages and tools for certified programming;
  • program analysis, program verification, and program synthesis;
  • program logics, type systems, and semantics for certified code;
  • logics for certifying concurrent and distributed systems;
  • mechanized metatheory, formalized programming language semantics, and logical frameworks;
  • higher-order logics, dependent type theory, proof theory, logical systems, separation logics, and logics for security;
  • verification of correctness and security properties;
  • formally verified blockchains and smart contracts;
  • certificates for decision procedures, including linear algebra, polynomial systems, SAT, SMT, and unification in algebras of interest;
  • certificates for semi-decision procedures, including equality, first-order logic, and higher-order unification;
  • certificates for program termination;
  • formal models of computation;
  • mechanized (un)decidability and computational complexity proofs;
  • formally certified methods for induction and coinduction;
  • integration of interactive and automated provers;
  • logical foundations of proof assistants;
  • applications of AI and machine learning to formal certification;
  • user interfaces for proof assistants and theorem provers;
  • teaching mathematics and computer science with proof assistants.

SUBMISSION GUIDELINES

Prior to the paper submission deadline, the authors should upload their anonymized paper in PDF format through the HotCRP system.

https://cpp2024.hotcrp.com/

The submissions must be written in English and provide sufficient detail to allow the program committee to assess the merits of the contribution. They must be formatted following the ACM SIGPLAN Proceedings format using the acmart style with the sigplan option, which provides a two-column style, using 10 point font for the main text, and a header for double blind review submission, i.e.,

\documentclass[sigplan,10pt,anonymous,review]{acmart}\settopmatter{printfolios=true,printccs=false,printacmref=false}

The submitted papers should not exceed 12 pages, including tables and figures, but excluding bibliography and clearly marked appendices. The papers should be self-contained without the appendices. Shorter papers are welcome and will be given equal consideration. Submissions not conforming to the requirements concerning format and maximum length may be rejected without further consideration.

CPP 2024 will employ a lightweight double-blind reviewing process following the process from previous years. To facilitate this, the submissions must adhere to two rules: (1) author names and institutions must be omitted, and (2) references to authors’ own related work should be in the third person (e.g., not “We build on our previous work …” but rather “We build on the work of …”).

The purpose of this process is to help the PC and external reviewers come to an initial judgment about the paper without bias, not to make it impossible for them to discover the authors if they were to try. Nothing should be done in the name of anonymity that weakens the submission or makes the job of reviewing it more difficult. In particular, important background references should not be omitted or anonymized. In addition, authors are free to disseminate their ideas or draft versions of their papers as usual. For example, authors may post drafts of their papers on the web or give talks on their research ideas. Note that POPL 2024 itself will employ full double-blind reviewing, which differs from the light-weight CPP process. This FAQ from previous SIGPLAN conference addresses many common concerns: https://popl20.sigplan.org/track/POPL-2020-Research-Papers#Submission-and-Reviewing-FAQ

We strongly encourage the authors to provide any supplementary material that supports the claims made in the paper, such as proof scripts or experimental data. This material must be uploaded at submission time, as an archive, not via a URL. Two forms of supplementary material may be submitted: (1) Anonymous supplementary material is made available to the reviewers before they submit their first-draft reviews. (2) Non-anonymous supplementary material is made available to the reviewers after they have submitted their first-draft reviews and have learned the identity of the authors.

Please use anonymous supplementary material whenever possible, so that it can be taken into account from the beginning of the reviewing process.

The submitted papers must adhere to the SIGPLAN Republication Policy (https://www.sigplan.org/Resources/Policies/Republication/) and the ACM Policy on Plagiarism (https://www.acm.org/publications/policies/plagiarism). Concurrent submissions to other conferences, journals, workshops with proceedings, or similar forums of publication are not allowed. The PC chairs should be informed of closely related work submitted to a conference or journal in advance of submission. One author of each accepted paper is expected to present it at the (possibly virtual) conference.

PUBLICATION, COPYRIGHT AND OPEN ACCESS

The CPP 2024 proceedings will be published by the ACM, and authors of accepted papers will be required to choose one of the following publication options: (1) Author retains copyright of the work and grants ACM a non-exclusive permission-to-publish license and, optionally, licenses the work under a Creative Commons license. (2) Author retains copyright of the work and grants ACM an exclusive permission-to-publish license. (3) Author transfers copyright of the work to ACM.

For authors who can afford it, we recommend option (1), which will make the paper Gold Open Access, and also encourage such authors to license their work under the CC-BY license. ACM will charge you an article processing fee for this option (currently, US$700), which you have to pay directly with the ACM. You don’t need to pay this fee if the corresponding author’s affiliating institution is part of ACM OPEN (https://libraries.acm.org/subscriptions-access/open-participants).

For everyone else, we recommend option (2), which is free and allows you to achieve Green Open Access, by uploading a preprint of your paper to a repository that guarantees permanent archival such as arXiv or HAL. This is anyway a good idea for timely dissemination even if you chose option 1.

The official CPP 2024 proceedings will also be available via SIGPLAN OpenTOC (http://www.sigplan.org/OpenTOC/#cpp).

For ACM’s take on this, see their Copyright Policy (http://www.acm.org/publications/policies/copyright-policy) and Author Rights (http://authors.acm.org/main.html).

AUTHORS TAKE NOTE: The official publication date is the date the proceedings are made available in the ACM Digital Library. This date may be up to two weeks prior to the first day of the conference. The official publication date affects the deadline for any patent filings related to published work.

CONTACT

For any questions please contact the two PC chairs:

The ACM SIGPLAN International Conference on Certified Programs and Proofs (CPP) covers all areas that consider formal verification and certification as an essential paradigm for their work. CPP spans areas of computer science, mathematics, logic, and education and brings together 100+ researchers and practitioners to present the latest developments in formal verification.

CPP welcomes corporate donations to help maintain and improve the overall experience at the conference. The money we get from corporate sponsors will generally be used to subsidize student attendance (e.g., registration waiving, which generally increases student participation), to pay for live streaming and recording CPP, and facilitate online interaction.

CPP Support Levels

Bronze – Suggested donation $1000

  • Company name and logo prominently displayed on the CPP website
  • Acknowledgment in the CPP PC chairs’ statement for the proceedings
  • Acknowledgment in the CPP chairs’ report talk
  • In case of an online/hybrid conference: video room for interacting with conference participants during breaks
  • In case of a physical conference: opportunity to display information material on a shared table near the registration desk or the conference room
  • One complimentary registration to CPP

Silver – Suggested donation $2500

Bronze benefits plus:

  • Acknowledgment as a sponsor of one invited talk
  • In case of a physical conference: dedicated table space for interacting with participants for one day of CPP
  • One additional complimentary registration to CPP (2 total)

Gold – Suggested donation $5000

Silver benefits plus:

  • Acknowledgment as a sponsor of all invited talks
  • In case of a physical conference: dedicated table space for interacting with participants for all days of CPP
  • One additional complimentary registrations to CPP (3 total)

Diamond (first come first serve, single sponsor) – Suggested donation $10000

Gold benefits plus:

  • Sponsor of the CPP dinner (in case of a physical conference)
  • An opportunity for a representative from the company to address the attendees for 5 minutes, immediately before or after the chairs’ report (virtual conference) or at the conference dinner (physical conference)
  • Potential to accommodate alternative arrangements, in coordination with POPL and subject to ACM guidelines
  • One additional complimentary registration to CPP (4 total)

Carbon offset (first come first serve, single sponsor) – Suggested donation $10000

Gold benefits plus:

  • A special thanks in the CPP PC chairs’ statement for the proceedings and CPP chairs’ report talk for helping minimize the climate impact of CPP 2023
  • Funds in excess of the gold level will be used to purchase carbon offsets

Sponsorship Policy

Sponsors help offset the considerable expense involved in staging the conference, reducing the financial barriers to participation and enhancing inclusivity. We aim to foster a diverse community with participants from varied disciplines, organizations, and geographic locations. We value and encourage participation from across academia, industry, government, and civil society. At the same time, outside contributions can raise concerns about the independence of the conference and the legitimacy the conference may confer on sponsors. We take these concerns seriously and have taken steps to maintain a transparent and appropriate relationship with our sponsors:

  • We acknowledge all sources of financial support.
  • We disclose all benefits that sponsors receive in exchange for their contribution.
  • We ensure that sponsors have no say over the paper selection process, the composition of the program committees, the choice of invited speakers, or the selection of award winners. The substance and structure of the conference are determined independently by the program committee using a rigorous, lightweight double-blind peer review process.
  • We only allow sponsors to contribute to a general fund and do not allow sponsors to further specify how their contributions should be spent.
  • We are grateful to receive financial support from organizations that respect our twin goals of inclusivity and independence.

Acknowledgment: CPP’s sponsorship policy is adapted from the ACM FAccT conference and used under a CC-BY 2.0 license.

Contact

Questions about how to support CPP may be directed to the conference chairs Amin Timany and Dmitriy Traytel.

Previous CPP conferences

  • CPP 2023, Boston, USA, January 16-17, 2023 (co-located with POPL’23)
  • CPP 2022, Philadelphia, USA, January 17-18, 2022 (co-located with POPL’22)
  • CPP 2021, Online, January 17-19, 2021 (co-located with POPL’21)
  • CPP 2020, New Orleans, USA, January 20-21, 2020 (co-located with POPL’20)
  • CPP 2019, Cascais/Lisbon, Portugal, January 14-15, 2019 (co-located with POPL’19)
  • CPP 2018, Los Angeles, USA, January 8-9, 2018 (co-located with POPL’18)
  • CPP 2017, Paris, France, January 16-17, 2017 (co-located with POPL’17)
  • CPP 2016, Saint Petersburg, Florida, USA, January 18-19, 2016 (co-located with POPL’16)
  • CPP 2015, Mumbai, India, January 13-14, 2015 (co-located with POPL’15)
  • CPP 2013, Melbourne, Australia, December 11-13, 2013 (co-located with APLAS’13)
  • CPP 2012, Kyoto, Japan, December 13-15, 2012 (collocation with APLAS’12)
  • CPP 2011, Kenting, Taiwan, December 7-9, 2011 (co-located with APLAS’11)

The official CPP proceedings since 2015 are publicly available via SIGPLAN OpenTOC.

Given Distinguished Paper Awards

Given Amazing Reviewer Awards

The CPP Manifesto (from 2011)

In this manifesto, we advocate for the creation of a new international conference in the area of formal methods and programming languages, called Certified Programs and Proofs (CPP). Certification here means formal, mechanized verification of some sort, preferably with the production of independently checkable certificates. CPP would target any research promoting formal development of certified software and proofs, that is:

  • The development of certified or certifying programs
  • The development of certified mathematical theories
  • The development of new languages and tools for certified programming
  • New program logics, type systems, and semantics for certified code
  • New automated or interactive tools and provers for certification
  • Results assessed by an original open source formal development
  • Original teaching material based on a proof assistant

Software today is still developed without precise specification. A developer often starts the programming task with a rather informal specification. After careful engineering, the developer delivers a program that may not fully satisfy the specification. Extensive testing and debugging may shrink the gap between the two, but there is no assurance that the program accurately follows the specification. Such inaccuracy may not always be significant, but when a developer links a large number of such modules together, these “noises” may multiply, leading to a system that nobody can understand and manage. System software built this way often contains hard-to-find “zero-day vulnerabilities” that become easy targets for Stuxnet-like attacks. CPP aims to promote the development of new languages and tools for building certified programs and for making programming precise.

Certified software consists of an executable program plus a formal proof that the software is free of bugs with respect to a particular dependability claim. With certified software, the dependability of a software system is measured by the actual formal claim that it is able to certify. Because the claim comes with a mechanized proof, the dependability can be checked independently and automatically in an extremely reliable way. The formal dependability claim can range from making almost no guarantee, to simple type safety property, or all the way to deep liveness, security, and correctness properties. It provides a great metric for comparing different techniques and making steady progress in constructing dependable software.

The conventional wisdom is that certified software will never be practical because any real software must also rely on the underlying runtime system which is too low-level and complex to be verifiable. In recent years, however, there have been many advances in the theory and engineering of mechanized proof systems applied to verification of low-level code, including proof-carrying code, certified assembly programming, local reasoning and separation logic, certified linking of heterogeneous components, certified protocols, certified garbage collectors, certified or certifying compilation, and certified OS-kernels. CPP intends to be a driving force that would facilitate the rapid development of this exciting new area, and be a natural international forum for such work.

The recent development in several areas of modern mathematics requires mathematical proofs containing enormous computation that cannot be verified by mathematicians in an entire lifetime. Such development has puzzled the mathematical community and prompted some of our colleagues in mathematics and computer science to start developing a new paradigm, formal mathematics, which requires proofs to be verified by a reliable theorem prover. As particular examples, such an effort has been made for the four-color theorem and has started for the sphere packing problem and the classification of finite groups. We believe that this emerging paradigm is the beginning of a new era. No essential existing theorem in computer science has yet been considered worth a similar effort, but it could well happen in the very near future. For example, existing results in security would often benefit from a formal development allowing us to exhibit the essential hypotheses under which the result really holds. CPP would again be a natural international forum for this kind of work, either in mathematics or in computer science, and would participate strongly in the emergence of this paradigm.

On the other hand, there is a recent trend in computer science to formally prove new results in highly technical subjects such as computational logic, at least in part. In whichever scientific area, formal proofs have three major advantages: no assumption can be missing, as is sometimes the case; the result cannot be disputed by a wrong counterexample, as sometimes happens; and more importantly, a formal development often results in a better understanding of the proof or program, and hence results in easier and better implementation. This new trend is becoming strong in computer science work, but is not recognized yet as it should be by traditional conferences. CPP would be a natural forum promoting this trend.

There are not many proof assistants around. There should be more, because progress benefits from competition. On the other hand, there is much theoretical work that could be implemented in the form of a proof assistant, but this does not really happen. One reason is that it is hard to publish a development work, especially when this requires a long-term effort as is the case for a proof assistant. It is even harder to publish work about libraries which, we all know, are fundamental for the success of a proof assistant. CPP would pay particular attention in publishing, publicizing, and promoting this kind of work.

Finally, CPP also aims to be a publication arena for innovative teaching experiences, in computer science or mathematics, using proof assistants in an essential way. These experiences could be submitted in an innovative format to be defined.