Smooth Calabi–Yau structures and the noncommutative Legendre transform

We elucidate the relation between smooth Calabi–Yau structures and pre-Calabi–Yau structures. We show that, from a smooth Calabi–Yau structure on an A_{\infty} -category A , one can produce a pre-Calabi–Yau structure on A ; as defined in our previous work, this is a shifted noncommutative version of an integrable polyvector field. We explain how this relation is an analog of the Legendre transform, and how it defines a one-to-one mapping, in a certain homological sense. For concreteness, we apply this formalism to chains on based loop spaces of (possibly non-simply connected) Poincaré duality spaces and fully calculate the case of the circle.