  This is a companion paper our previous submission "\infty-categories
monoidales rigides et caracteres de Chern", in which we give a comparison
between functions on the derived loop space of a smooth scheme of caracteristic
zero, and its algebraic de Rham cohomology. As a consequence we obtain
functorial and multiplicative versions of the HKR decomposition theorem
relating Hochschild homology and Hodge cohomology.
