Buongiorno, Allego, per gli interessati, l'annuncio della quarta edizione di CATA, che si svolgerà a Pisa, presso il centro De Giorgi dal 22 al 25 Giugno 2026. A presto, Carlo _____________________________________________ Dear All, This is to announce the workshop *Combinatorial Algebraic Topology, and Applications IV <https://indico.sns.it/event/134/> *(CATA IV), that will be held at Centro De Giorgi in Pisa (IT) from June 22nd to 25th, 2026. The list of speakers includes: Valentina Bais (SISSA) Bruno Benedetti (University of Miami) Jelena Grbic (University of Southampton) Dmitrii Korshunov (Institut de mathématiques de Jussieu - Paris Rive Gauche) Jean-Baptiste Meilhan (Université Grenoble Alpes) Pegah Pournajafi (Collège de France) Francesca Pratali (Universiteit Utrecht) Anne-Laure Thiel (Université Bourgogne Europe) Francesco Vaccarino (Politecnico di Torino) So Yamagata (Fukuoka University) Registration is available at the *REGISTRATION* <https://indico.sns.it/event/134/> page. Registration is free, although mandatory, due to restrictions on the number of participants. *The deadline for registration is the 30th of April 2026*, and it will be confirmed after expiration. Interested participants can apply for a contributed talk. Limited funding might be available to early registered participants, priority will be given to junior participants and contributed speakers. *The deadline to apply for funding is the 31st of March 2026.* For further questions, please write to cata.organisers@gmail.com. Looking forward to seeing you in Pisa. The organizers, Luigi Caputi, Carlo Collari and Giuliamaria Menara