Dear colleagues, We are pleased to announce the XVI Portuguese Category Seminar, which will take place at the Centre for Mathematics, University of Coimbra, on 12–14 November 2026. We welcome contributions on category theory and its connections with algebra, topology, logic and computer science. Registration is free. The key dates are: - Abstract submission deadline: 29 October 2026 - Notification of acceptance: by 3 November 2026 - Registration deadline: 5 November 2026 Both the abstract submission and registration deadlines are at 23:59, Coimbra time. Registration is required for all participants, including those attending without giving a talk. The registration form, abstract template and further details are available on the conference website: https://flnlucatelli.github.io/2026/pcs.html To register or propose a talk, please email Maria Manuel Clementino ( mmc@mat.uc.pt) with the subject PCS-2026 SUBMISSION, including the completed form in the body of the email. Talk proposals should also include the abstract’s LaTeX source and compiled PDF as attachments. Participants attending without proposing a talk need only send the completed form. We would be grateful if you could circulate this announcement among colleagues and students who might be interested. We look forward to seeing you at the seminar! Best regards, Fernando Lucatelli Nunes On behalf of the organising committee