Abstract
I'll report on a project I'm carrying out with María-Inés de Frutos Fernández to formalize the theory of divided powers. Discovered by Cartan in a context of algebraic topology, this algebraic tool was developed in the 1960s by Roby and is at the heart of the construction of crystalline cohomology. In particular, I will discuss the construction of divided powers on the augmentation ideal of the divided-power algebra.