WLP @ KI2022 in Trier#WLP22
Workshop at the 45th German Conference on Artificial Intelligence

The workshops on (constraint) logic programming serve as the scientific forum of the annual meeting of the Society of Logic Programming (GLP, Gesellschaft fuer Logische Programmierung e.V.). They bring together researchers (not only from Germany) interested in logic programming, constraint programming, and related areas like databases, artificial intelligence, and operations research.

Contributions are welcome on all theoretical, experimental, and application aspects of logic and constraint logic programming. The topics include, but are not limited to the following areas:

  • Logic and Constraint Logic Programming Languages and Extensions
  • Knowledge Representation and Non-monotonic Reasoning
  • Applications and Application Areas of (C)LP
  • Implementations

In this year, the workshop is organised as part of the 45th German Conference on Artificial Intelligence (KI2022) in Trier. The technical program of the workshop will include invited talks, presentations of refereed papers and demo presentations.

Previous WLP Editions:

WLP 2021 (virtual/Berlin, Germany), WLP 2020 (Bamberg, Germany), WLP 2019 (Cottbus, Germany), WLP 2018 (Berlin, Germany), WLP 2017 (Würzburg, Germany), WLP 2016 (Leipzig, Germany), WLP 2015 (Dresden, Germany), WLP 2014 (Wittenberg, Germany), WLP 2013 (Kiel, Germany), WLP 2012 (Bonn, Germany), WLP 2011 (Vienna, Austria), WLP 2010 (Cairo, Egypt), WLP 2009 (Potsdam, Germany), WLP 2008 (Dresden, Germany), WLP 2007 (Würzburg, Germany), WLP 2006 (Vienna, Austria), WLP 2005 (Ulm, Germany), WLP 2004 (Potsdam, Germany), WLP 2002 (Dresden, Germany), WLP 2001 (Kiel, Germany), WLP 2000 (Berlin, Germany), WLP'99 (Würzburg, Germany), WLP'98 (Vienna, Austria), WLP'97 (Munich, Germany), WLP'95 (Vienna, Austria), ...


For each accepted workshop paper at least one author needs to register for the conference via the KI2022 website. Early Bird registration will be open until August 15th and final registration will be open until August 20th.


The topics of interest include (but are not limited to):

  • Logic programming
  • Constraint programming
  • Deductive databases, data mining
  • Extensions of declarative languages, objects
  • Multi-paradigm declarative programming
  • Foundations, semantics, nonmonotonic reasoning, dynamics
  • Parallelism, concurrency
  • Program analysis, abstract interpretation
  • Program transformation, partial evaluation, meta-programming
  • Specification, verification, declarative debugging
  • Knowledge representation, machine learning
  • Interaction of declarative programming with other formalisms (e.g., agents, XML, Java)
  • Implementation of declarative languages
  • Advanced programming environments and tools
  • Software technique for declarative programming
  • Applications
  • Lessons learned by teaching in the addressed fields

The primary focus is on new and original research results but submissions describing innovative products, prototypes under development, application systems, or interesting experiments (e.g., benchmarks) are also encouraged.

Schedule and Accepted Papers

Monday, 19th

Session I: Datalog

Chair: Falco Nogatz
Deutsches Forschungszentrum für Künstliche Intelligenz, Kaiserslautern


Two Programs, one Distribution? - On Distinguishing Structures of Probabilistic Logic Programs

Kilian Rueckschloss and Felix Weitkämper
LMU Munich

We present a criterion for two structures of probabilistic logic programs, i.e.~programs with unspecified probabilities, to induce different sets of distributions. To this end we associate to each program structure a datalog program, which we call the Pearl identifier. We then obtain that faithfully indistinguishable program structures yield equivalent Pearl identifiers. Moreover, we argue that the notion of faithful indistinguishability is sufficiently close to the notion of two program structures inducing the same set of distributions. Hence, we reduce our initial problem to the equivalence of datalog programs, a semi-decidable problem.

  • Probabilistic Logic Programming
  • Equivalence of Probabilistic Logic Programs
  • Faithful Indistinguishability
  • Markov Equivalence
  • Causal Structure Discovery

Microlog Abstract Execution and State Enumeration

Mario Wenzel
University of Halle

In this paper we describe a method of abstract execution for Microlog programs by attaching conditions to derived facts. This method is used to enumerate the possible state space of a Microlog program. The set of states is reduced by considering return values from the environment as abstract memory positions, possibly collapsing an untenable number of states to just a few.
Microlog is a deductive database language with a strong logic foundation based on Datalog extended with a representation of time and calls to external functions that may be used to control sensors and actors.

  • Datalog
  • Logic Programming
  • Microlog
  • Finite State Machines
  • Termination



Session II: Prolog

Chair: Mario Wenzel
University of Halle


XML-Processing Using Field Notation Grammars Applied to Tennis Data

Daniel Weidner and Dietmar Seipel
University of Würzburg

XML is a well-known and frequently used data format for semi-structured, complex and nested data. In this paper, we store tennis data in an XML format; a match is structured into sets, games, and points, and for every point the location of the tennis field and the trajectory of the ball is given in some way. In earlier work we had implemented an analysis of tennis data, that were entered by hand, using the declarative logic programming toolkit Declare. Recently, we have added an automatic recognition of the tennis data from tennis videos using convolutional neural networks (CNNs). Unfortunately, the automatically obtained XML files from the CNN are unclean and cannot be used for the intended analysis. Coordinates are not given in a bird's-eye perspective, but as recorded from a camera behind the court. Moreover, the ball trajectories have to be reduced to the moments when the ball is hit - instead of one position per video frame, i.e. 24 positions per second (the ball is hit once about every 1.5 seconds, e.g. a rally with 9 hits can take 13 - 15 seconds). Also, the CCN frequently fails in recognizing the ball or the tennis field. In this paper, we present a process of XML transformation based on field notation grammars. We transformed the unclean data obtained from the convolutional neural network into structured clean data which can then be used for further processing, like data mining. Our transformation uses field notation grammars (FNGs) and solves linear equations to project x- and y- coordinates into the plane. FNGs have been implemented in Declare using Prolog; they extend the common path notation Xpath of XML, and they combine XML-processing with Prolog.

  • Prolog
  • XML Processing
  • Field Notation Grammars

Mutating Sample Solutions to Improve Prolog Exercise Tasks and Their Test Suites

Ivan Khu Tanujaya, Janis Voigtländer, and Oliver Westphal
University of Duisburg-Essen

We report on a tool for analyzing and adapting test suites for Prolog in an educational setting. The key idea is to mutate a known-correct sample solution in order to "simulate" possible student mistakes, and use that to "harden" the test suite that an e-learning system uses for judging submissions and giving feedback.

  • Prolog
  • Teaching
  • Testing

A Jupyter Kernel for Prolog

Anne Brecklinghaus and Philipp Koerner
University Düsseldorf

Benefits of literate programming are well-known: by combining source code and documentation, concepts can be introduced in a more comprehensible way to the reader. Motivated by rendering our Prolog applications and teaching examples more readable, we implemented a Jupyter kernel for SICStus Prolog. In this paper, we will give a feature overview of this kernel, discuss particularities caused by Prolog’s execution mechanism and report on our experiences porting the kernel to SWI-Prolog.

  • Literate Programming
  • Prolog
  • Jupyter Notebook
  • Integration



Mitgliederversammlung der Gesellschaft für Logische Programmierung (GLP) e.V.

Dietmar Seipel
University of Würzburg


Standard Submission of Papers

19th June 2022 4th July 2022

Notification of Acceptance for Standard Submissions

1st August 2022

Late Submission of Papers

8th August 2022

Notification of Acceptance for Late Submissions

28th August 2022

Camera-ready Papers

7th September 2022


19th September 2022, 09:00–12:00

Submission Guidelines

Papers must describe original work, be written and presented in English, and must not substantially overlap with papers that have been published or that are simultaneously submitted to a journal, conference, or workshop with refereed proceedings. Work that already appeared in unpublished or informally published workshop proceedings may be submitted (please contact the PC chairs in case of questions).

Full papers should consist of up to 12 pages, system descriptions or short papers should be no longer than 6 pages (excluding references). Formatting should follow the GI-LNI style and guidelines which are available here, along with formatting templates and style files.

Authors should submit an electronic copy of the full paper in PDF. Papers should be submitted via the EasyChair conference management system (https://easychair.org/conferences/?conf=ki2022). Please select track W9: 36th Workshop on (Constraint) Logic Programming. Submission for workshops is possible though the EasyChair website indicates the deadlines of the KI2022 main event (May 16 and 23).

The workshop is running a single-blind review process. Submitted papers will be judged on the basis of significance, relevance, correctness, originality, and clarity. They should include a clear identification of what has been accomplished and why it is significant. All accepted papers will be published in a technical report. KI2022 plans the publication of selected workshop papers in the GI-LNI proceedings series after the KI2022 conference. Authors of papers selected for publication in this selected GI-LNI series will later get a possibility to submit an extended version of the paper disregarding their original submission format.

The WLP is also open to people who would like to attend without submitting a paper as discussion of the topic will play a major role.

Late Submission still open! The organisers of the main conference KI2022 recently decided to go fully virtual. As WLP participation no longer requires travel planning and travel expenses, we announce a second, late submission deadline WLP. In addition to the already passed standard submission, this allows authors to still contribute on a tighter schedule of publication. Besides the later notification, contributions of late submission will receive the same treatment as standard submissions, including the normal review process.


Workshop Chairs

Falco Nogatz (DFKI, Germany)
Mario Wenzel (University of Halle, Germany)

Program Committee of WLP 2022

Slim Abdennadher (German University Cairo, Egypt)
Salvador Abreu (University of Évora, Portugal)
Stefan Brass (University of Halle, Germany)
Thom Frühwirth (Ulm University, Germany)
Ulrich Geske (University of Potsdam, Germany)
Michael Hanus (University of Kiel, Germany)
Petra Hofstedt (BTU Cottbus-Senftenberg, Germany)
Ulrich John (International University of Applied Sciences Berlin, Germany)
Philipp Koerner (University Düsseldorf, Germany)
Sibylle Schwarz (HTWK Leipzig, Germany)
Dietmar Seipel (University of Würzburg, Germany)
Hans Tompits (TU Wien, Austria)
Felix Weitkämper (LMU München, Germany)
Armin Wolf (Fraunhofer FOKUS, Germany)

Location and Venue

University of Trier – Rhineland-Palatinate – Germany – ❤ of Europe

Trier is the oldest city in Germany with more than 2000 years of history. Today, with a population of about 110,000, Trier is an episcopal and university city with more than 22,000 students. Situated on the Moselle (Mosel) River, not far from Luxembourg, the city is on the geographic edge of Germany, but in the heart of Europe.


Campus I (Main Campus)

Universitätsring 15

54296 Trier, Germany


Trier is a very popular destination all year round, especially in the summer and fall seasons. During this time, hotel contingents become particularly scarce. Therefore, we recommend booking accommodation very early. A list of hotels with reserved contingents is given at the website of KI2022.

Additional details

For additional information information for guests, we refer to the KI2022 website.

WLP @ KI2022

September 2022, Trier