ScalingStacks

Proposition 6.6. In any 2d TFT $\mathcal{Z}$, the object $\mathcal{Z}(S^{1})\in\mathcal{C}$ is an algebra over the framed $\mathcal{E}_{2}$-operad (in particular, over the $\mathcal{E}_{2}$-operad).