ModRef 2025 is the 24th in a series of workshops on Constraint Modelling and Reformulation organized as part of CP 2025, the 31st International Conference on Principles and Practice of Constraint Programming. It will be held on August 11, 2025, directly preceding the CP conference.

The importance of modelling and model reformulation is widely recognised in many domains, such as for CP, MIP, SAT, SMT and other kinds of general-purpose solvers. There has been significant research effort in recent years into modelling and model reformulation, such as automating techniques used by expert modellers, and developing tools and techniques to target multiple types of solvers from one model.

The purpose of ModRef is to be a forum for all kinds of work in modelling, including new models or new modelling ideas for any amenable problem (whether a new application or a classic benchmark), reformulation techniques to improve the performance of models when solved by general-purpose solvers, and automated modelling techniques, tools, and languages. We solicit original papers that contribute to the understanding of modelling or model reformulation.

Workshop topics include:

• Application papers describing interesting problems and interesting ways to model them;
• Contributions to understanding modelling that could guide the manual or automatic formulation of models;
• Identification of the criteria that should be used in evaluating models and the design of pragmatic techniques that facilitate the choice and possible combination among alternative models;
• Design of higher-level modelling languages;
• Automatic reformulation techniques; and
• Techniques which allow automatically targeting multiple kinds of solvers from a single declarative model.

Important Dates

Abstract Submission	June 8, 2025
Paper Submission	June 15, 2025
Notification of acceptance/rejection	June 25, 2025
Camera ready version	August 1, 2025
Workshop day	August 11, 2025

Call for Papers

This year ModRef will again accept paper submissions. In addition to the presentation of research results, we especially welcome submissions of novel (ongoing) work, recent breakthroughs, future directions, and descriptions of interesting aspects of existing systems.

There are three types of paper submissions: extended abstracts (at most two pages), short papers (at most eight pages) and long papers (at most fifteen pages). References are not part of the page limit. Papers are submitted through OpenReview as PDF files following LIPIcs guidelines. There is no requirement for papers to be anonymised before submission.

We also accept (and encourage) non-traditional electronic submissions, such as interactive works/tool demonstrations. In this case, please contact the chairs to discuss the suitability of your submission for ModRef.

All submissions will be reviewed, and those that are well-written and make a worthwhile contribution to the topic of the workshop will be accepted for publication in the workshop proceedings, which will be available electronically on this website. Accepted contributions will be allowed a time slot for a presentation at the workshop.

Paper Submission Link: https://openreview.net/group?id=a4cp.org/CP/2025/Workshop/ModRef

Invited Talk

Marijn Heule, Carnegie Mellon University

Solving Problems in Discrete Geometry Using SAT

Accepted Papers

TBA

Schedule

TBA

Program Committee

María Andreína Francisco Rodríguez (Chair)	Uppsala University
Ian Gent (Chair)	University of St Andrews
Özgür Akgün	University of St Andrews
Ramiz Gindullin	Uppsala University
Christopher Jefferson	University of St Andrews
Jan Kronqvist	KTH
Jimmy Lee	The Chinese University of Hong Kong
Kevin Leo	Monash University
Justin Pearson	Uppsala University
Felix Ulrich-Oltean	University of York
Hélène Verhaeghe	UCLouvain
Mateu Villaret	Universitat de Girona