Diamond open access
Diamond open access is a non-commercial scientific publishing model in which research publications are freely accessible upon publication, with no subscription fees for readers and no article processing charges (APCs) for authors. This model operates primarily through the support of public institutions.
All mathematics publications from centre Mersenne are diamond open access. They are available in Numdam one year after publication.
Subscribe to open (S2O)
The S2O (Subscribe-to-Open) model is based on the principle that if a sufficient number ofsubscriptions to a journal is obtained for a given year, all content published in that journal during that year becomes freely accessible, permanently.
In practical terms, S2O operates on the basis of a subscription threshold set by the publisher or publishing house:
- if this number reaches a sufficient support threshold (corresponding to the journal's financial break-even point), all articles published during the year are made freely available on the journal's website.
- if this threshold is not reached, access remains restricted to subscribers.
The process starts from scratch each year: in other words, a journal may be open one year, but not in subsequent years.
For the publishers listed below, some of the mathematics journals we distribute on Numdam and/or Geodesic are freely accessible via this model:
Buy to Open (B2O)
The B2O (Buy-to-Open) model is based on the idea that each purchase contributes to making the books accessible to all.
This choice was made by the SMF thanks to financial support from the CNRS to make its book collections (Cours Spécialisés, Panoramas & Synthèses, Séminaires et Congrès) freely available. Thus:
- Electronic versions of books published before 31 December 2020 can be downloaded free of charge;
- Recent books will also become available free of charge once a certain number of paper copies have been sold;
- Paper books remain available for purchase.
