As part of EDP Sciences’ ongoing commitment to furthering open science, this news update is the latest in our “Road to Open” series, which highlights developments in open access publishing through models such as Subscribe to Open (S2O). This edition focuses on the continued, though increasingly fragile, support for open access in mathematics journals. Despite a notably more difficult renewal campaign in 2025, the collaborative efforts of libraries, academic institutions, and the wider mathematical community have once again made it possible to disseminate high-quality research without article processing charges. Join the conversation on social media with #RoadToOpen.

EDP Sciences and the Société de Mathématiques Appliquées et Industrielles (SMAI) are pleased to confirm that all six mathematics journals will remain open access in 2025 under the Subscribe to Open (S2O) model. This outcome, achieved in the face of considerable difficulty, reflects a continued, though increasingly fragile, commitment to equitable and sustainable open access from our subscribers.

This year’s renewal campaign was markedly more challenging than in previous years, prompting reflection on the long-term resilience of the S2O model. While we ultimately succeeded in renewing the journals, the process highlighted a potential loss of momentum for S2O across our subscriber base. In particular, ESAIM: Control, Optimisation and Calculus of Variations (COCV) could only be sustained thanks to the intervention of SMAI and Insmi (CNRS Mathematics), which stepped in to financially support the journal.

We are therefore especially grateful to the libraries and institutions that chose to maintain their support this year. Their continued commitment to the Subscribe to Open model has enabled the publication of high-quality mathematical research in open access without article processing charges (APCs). At a time of growing uncertainty, their backing is more important than ever and remains the cornerstone of S2O’s collaborative and equitable approach to open science.

“We acknowledge that sustaining S2O is becoming more challenging and requires renewed advocacy and engagement,” said Agnès Henri, Managing Director at EDP Sciences. “Nonetheless, the success of the 2025 renewals is evidence of the strength of our partnerships and the shared belief in fair and affordable open access.”

The transition of the mathematics journals to open access is supported not only by library subscriptions, but also by the continued engagement of the French mathematical community. This includes funding from academic sponsors such as Insmi and the CERMICS Lab at École des Ponts ParisTech, as well as support through the French National Agreement. We are also grateful to our Advisory Board, whose feedback and guidance have been invaluable in shaping and sustaining our implementation of the S2O model during this challenging year.

Amandine Véber, Director of Publications at SMAI, commented: “This year’s experience highlights both the promise and the precarity of the S2O model. SMAI remains committed to supporting open access and to our collaboration with EDP Sciences to ensure a sustainable path forward.”

Transparency remains central to EDP Sciences’ implementation of S2O. An updated Transparency Report reflecting 2024 data will be made publicly available in line with our open science commitments later this year.

The six mathematics journals participating in the S2O programme for 2025 are: ESAIM: Control, Optimisation and Calculus of Variations; ESAIM: Mathematical Modelling and Numerical Analysis; ESAIM: Probability and Statistics; Mathematical Modelling of Natural Phenomena; RAIRO – Operations Research; and RAIRO – Theoretical Informatics and Applications.