Fifth Workshop on Proof eXchange for Theorem Proving

PxTP 2017

Affiliated to the Tableaux, FroCoS and ITP conferences

23-24 September 2017, Brasilia, Brazil


The PxTP workshop brings together researchers working on various aspects of communication, integration, and cooperation between reasoning systems and formalisms.

The progress in computer-aided reasoning, both automated and interactive, during the past decades, made it possible to build deduction tools that are increasingly more applicable to a wider range of problems and are able to tackle larger problems progressively faster. In recent years, cooperation of such tools in larger verification environments has demonstrated the potential to reduce the amount of manual intervention. Examples include the Sledgehammer tool providing an interface between Isabelle and (untrusted) automated provers, and also collaboration between HOL Light and Isabelle in the formal proof of the Kepler conjecture.

Cooperation between reasoning systems relies on availability of theoretical formalisms and practical tools to exchange problems, proofs, and models. The PxTP workshop strives to encourage such cooperation by inviting contributions on suitable integration, translation and communication methods, standards, protocols, and programming interfaces. The workshop welcomes the interested developers of automated and interactive theorem proving tools, developers of combined systems, developers and users of translation tools and interfaces, and producers of standards and protocols. We are also interested both in success stories and in descriptions of the current bottlenecks and proposals for improvement.


Topics of interest for this workshop include all aspects of cooperation between reasoning tools, whether automatic or interactive. More specifically, some suggested topics are:

  • applications that integrate reasoning tools (ideally with certification of the result);
  • interoperability of reasoning systems;
  • translations between logics, proof systems, models;
  • distribution of proof obligations among heterogeneous reasoning tools;
  • algorithms and tools for checking and importing (replaying, reconstructing) proofs;
  • proposed formats for expressing problems and solutions for different classes of logic solvers (SAT, SMT, QBF, first-order logic, higher-order logic, typed logic, rewriting, etc.);
  • meta-languages, logical frameworks, communication methods, standards, protocols, and APIs related to problems, proofs, and models;
  • comparison, refactoring, transformation, migration, compression and optimization of proofs;
  • data structures and algorithms for improved proof production in solvers (e.g. efficient proof representations);
  • (universal) libraries, corpora and benchmarks of proofs and theories;
  • alignment of diverse logics, concepts and theories across systems and libraries;
  • engineering aspects of proofs (e.g. granularity, flexiformality, persistence over time);
  • proof certificates;
  • proof checking;
  • mining of (mathematical) information from proofs (e.g. quantifier instantiations, unsat cores, interpolants, ...);
  • reverse engineering and understanding of formal proofs;
  • universality of proofs;
  • origins and kinds of proofs (e.g. (in)formal, automatically generated, interactive, ...);
  • Hilbert's 24th Problem (i.e. what makes a proof better than another?);
  • social aspects (e.g. community-wide initiatives related to proofs, cooperation between communities, the future of (formal) proofs);
  • applications relying on importing proofs from automatic theorem provers, such as certified static analysis, proof-carrying code, or certified compilation;
  • application-oriented proof theory;
  • practical experiences, case studies, feasibility studies;
  • Submissions

    Researchers interested in participating are invited to submit either an extended abstract (up to 8 pages) or a regular paper (up to 15 pages). Submissions will be refereed by the program committee, which will select a balanced program of high-quality contributions. Short submissions that could stimulate fruitful discussion at the workshop are particularly welcome. We expect that one author of every accepted paper will present their work at the workshop.

    Submitted papers should describe previously unpublished work, and must be prepared using the LaTeX EPTCS class. Papers should be submitted via EasyChair, at the PxTP'2017 workshop page. Accepted regular papers will appear in an EPTCS volume.

    Important Dates

    Invited speakers


    Registration to PxTP is part of the Tableaux/FroCoS/ITP registration process.


    Click on the titles of the talks to download the papers.

    Saturday, 23 September 2017

    9:00-10:30 Invited speaker: Gilles Dowek
    Analyzing logics, analyzing theories, and analyzing proofs

    10:30-11:00 break
    11:00-11:30 Haniel Barbosa, Jasmin Christian Blanchette and Pascal Fontaine
    Scalable Fine-Grained Proofs for Formula Processing

    11:30-12:00 Haniel Barbosa, Jasmin Christian Blanchette, Simon Cruanes, Daniel El Ouraoui and Pascal Fontaine
    Language and proofs for Higher-order SMT (work in progress)

    12:00-12:30 Pascal Fontaine and Cesare Tinelli
    Presentation and Discussion of the Current Picture of the Future SMT-LIB 3

    12:30-14:00 lunch break
    14:00-14:45 Tomer Libal and Xaviera Steele
    Determinism in the Certification of UNSAT Proofs

    14:45-15:30 Giselle Reis and Bruno Woltzenlogel Paleo
    Complexity of Translations from Resolution to Sequent Calculus

    15:30-16:00 break
    16:00-16:45 Dennis Müller, Colin Rothgang, Yufei Liu and Florian Rabe
    Alignment-based Translations Across Formal Systems Using Interface Theories

    16:45-17:30 PxTP Business Meeting

    Sunday, 24 September 2017

    9:00-10:30 Invited speaker: Cesare Tinelli
    Increasing automation in Coq via trustworthy cooperation with external automated reasoners

    10:30-11:00 break
    11:00-11:45 Robert Lewis
    An extensible ad hoc interface between Lean and Mathematica

    11:45-12:30 Silvio Ghilardi and Elena Pagani
    Counter Simulations via Higher Order Quantifier Elimination: a preliminary report

    12:30-14:00 lunch break

    Program Committee

    Previous Editions