ModRef 2023 is the 22nd in a series of workshops on Constraint Modelling and Reformulation organized as part of CP 2023, the 29th International Conference on Principles and Practice of Constraint Programming. It will be held on August 27th, directly preceding the CP conference.

The importance of modelling and model reformulation is widely recognised, particularly for CP but also for 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 constraint modelling, including new models or new modelling ideas for any amenable problem (whether a new application or a classic benchmark), constraint 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 constraint 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.

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 EasyChair, as a PDF file following LIPIcs guidelines.

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. The proceedings will be available electronically at CP 2023. Accepted contributions will be allowed a time slot for a presentation at the workshop. In-person presentation is preferable, but we will allow remote presentation of papers when necessary.