We invite you to submit your work to ModRef 2026, the 25th workshop on Constraint Modelling and Reformulation, which will be held on 19th July 2026 in Lisbon, Portugal, as part of FLOC26.

The purpose of ModRef is to be a forum for all kinds of work in modelling for CP, MIP, SAT, SMT, and other general-purpose solvers, 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.

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.
  • Long papers: at most fifteen pages.

References are not part of the page limit. 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.

Papers should be submitted through HotCRP as PDF files following LIPIcs guidelines. There is no requirement for papers to be anonymised before submission.

All submissions will be reviewed, and those that are well-written and make a worthwhile contribution to the topic of the workshop will be allowed a time slot for a presentation at the workshop. Accepted papers will be included in non-archival electronic workshop proceedings, which will be available on ModRef’s web site. You can see some of the past accepted papers to give you an idea of the kind of contributions shared over recent years.

For more information, please see our web site https://2026.modref.org/

If you have any questions, please contact us at jordicoll@udg.edu and felix.ulrich-oltean@york.ac.uk

Jordi Coll and Felix Ulrich-Oltean Co-chairs