The Hochschild cohomology of a Poincar\'e algebra

Abstract

In this note, we define the notion of a cactus set, and show that its geometric realization is naturally an algebra over Voronov's cactus operad, which is equivalent to the framed 2-dimensional little disks operad $\mathcal{D}_2$. Using this, we show that the Hochschild cohomology of a Poincar\'e algebra A is an algebra over (the chain complexes of) $\mathcal{D}_2$.