Séminaire Cambium, Inria Paris BJ09 Vendredi 3 octobre, 10h00 Yannick Zakowski Inria Coinduction in Rocq in 2025 A user's first contact with proofs by coinduction in Rocq can be confusing, if not disheartning. Seemingly valid proofs are mysteriously refused at "Qed-time", leading to a particularly painful debugging experience---especially if one is new to coinduction altogether and struggles to figure out if the proof is morally wrong, or simply rubbing off the system the wrong way. Luckily, this state of affair is vastly a thing of the past! Library support has been introduced in the ecosystem to vastly alleviate these difficulty, leaving the user with the noble half of the task: figuring out a sound proof. In this talk, we will discuss the foundations and implementation of coinductive proofs for coinductive relations in Rocq. We should skim through Knaster-Tarski fixpoint theorem, Hur et al.'s parametric coinduction, Pous's companion, and Schäfer and Smolka's tower induction. The talk will contain no novel research material, but will rather be a sort of tutorial, focusing on the use of Damien Pous's library `coq-coinduction`. It will notably use material developped at other occasions with Damien Pous. Vous pouvez vous abonner à nos annonces de séminaires: http://cambium.inria.fr/seminar.html Nos séminaires sont accessibles en ligne en direct via le lien ci-dessus.