HCVS Home Page

July 17, 2014 · Vienna, Austria



Most Program Verification and Synthesis problems of interest can be modeled directly using Horn clauses and many recent advances in the CLP and CAV communities have centered around efficiently solving problems presented as Horn clauses.

This workshop aims to bring together researchers working in the two communities of Constraint/Logic Programming (e.g., ICLP and CP) and Program Verification community (e.g., CAV, TACAS, and VMCAI) on the topic of Horn clause based analysis, verification and synthesis.

Horn clauses for verification and synthesis have been advocated by these two communities in different times and from different perspectives and this workshop is organized to stimulate interaction and a fruitful exchange and integration of experiences.

Aims and Scope

Topics of interest include, but are not limited to the use of Horn clauses, constraints, and related formalisms in the following areas:

  • Analysis and verification of programs in various programming paradigms (e.g., imperative, object-oriented, functional, logic, higher-order, concurrent)
  • Program synthesis
  • Program testing
  • Program transformation
  • Constraint solving
  • Type systems
  • Case studies and tools
  • Challenging problems

We solicit regular papers describing theory and implementation of Horn-clause based analysis, tool descriptions and extended abstracts describing work-in-progress, and finally also position papers covering previously published results that are of interest to the workshop.

Invited speakers

  • Daniel Kröning (University of Oxford)

    Title: Proof and Refutations for Horn-clause Encodings of Reachability Problems

    Abstract: The talk focuses on solving program reachability problems by means of a Horn-clause style program encoding and suitable decision procedures. We will first examine a way to construct the necessary invariants using a combination of abstract interpretation and DPLL-style satisfiability solving. We will then consider a technique for generating counterexamples, and ways how these counterexamples can be used for proof in a synergistic fashion. I will finally show an encoding for concurrent systems based on partial-order semantics.

  • Michael Leuschel (Heinrich-Heine-Universität Düsseldorf)

    Title: Towards Constraint-Solving over Higher-Order Unbounded Datatypes using Formal Methods Tools

    Abstract: We argue that formal methods such as B can be used to conveniently express a wide range of constraint satisfaction problems. We also show that some problems can be solved quite effectively by existing formal methods tools such as Alloy or ProB. We illustrate our claim on several examples. Our approach is particularly interesting when a high assurance of correctness is required. Indeed, validation and double checking of solutions is available for certain formal methods tools and formal proof can be applied to establish important properties or provide unambiguous semantics to problem specifications. The experiments also provide interesting insights about the effectiveness of existing formal method tools, and highlight interesting avenues for future improvement.


The proceedings of HCVS 2014 have been published as EPTCS 169.


Invited talk

9.00 - 10.15 (Location: FH, Seminarraum 134A)
Daniel Kröning.
Proof and Refutations for Horn-clause Encodings of Reachability Problems

10.15 - 10.45  Coffee Break

Technical Session 1 (Location: FH, Seminarraum 134A)

10.45 - 11.20 (35 minutes)
Hossein Hojjat, Philipp Ruemmer, Pavle Subotic and Wang Yi.
Horn Clauses for Communicating Timed Systems

11.20 - 11.55 (35 minutes)
Emanuele De Angelis, Fabio Fioravanti, Jorge A. Navas and Maurizio Proietti
Verification of Programs by Combining Iterated Specialization with Interpolation

11.55 - 12.30 (35 minutes)
Alan Perotti, Guido Boella and Artur D'Avila Garcez
Runtime Verification Through Forward Chaining

12.30 - 13.05 (35 minutes)
Ashutosh Gupta, Corneliu Popeea and Andrey Rybalchenko
Generalised Interpolation by Solving Recursion-Free Horn Clauses

13.00 - 14.30 Lunch

Invited talk (shared with VPT)

14.30 - 15.30 (Location: FH, Seminarraum 134A)
Michael Leuschel (Heinrich-Heine-Universität Düsseldorf)
Towards Constraint-Solving over Higher-Order Unbounded Datatypes using Formal Methods Tools

15.30 - 16.00  Coffee Break

Technical Session 2 (Location: FH, Seminarraum 134A)

16.00 - 16.35 (35 minutes)
Bishoksan Kafle and John P. Gallagher
Convex polyhedral abstractions, specialisation and property-based predicate splitting in Horn clause verification

16.35 - 17.10 (35 minutes)
Temesghen Kahsai, Pierre-Loic Garoche and Arie Gurfinkel
Synthesizing Modular Invariants for Synchronous Code

17.10 - 18.00
Final discussion and plans for future editions

Program Committee

Important Dates

Submission deadline: May 25, 2014  *extended*
Workshop: July 17, 2014 · Vienna, Austria

Submission Format: up to 12 pages plus bibliography, in EPTCS format.

Original accepted papers will be published electronically as a volume in the Electronic Proceedings in Theoretical Computer Science (EPTCS) series, see http://www.eptcs.org/

Authors of accepted papers are required to ensure that at least one of them will be present at the workshop.

Papers must be submitted through the EasyChair system using the web page








Last update: Fabio Fioravanti 2/12/2014