  We establish a Quillen equivalence relating the homotopy theory of Segal
operads and the homotopy theory of simplicial operads, from which we deduce
that the homotopy coherent nerve functor is a right Quillen equivalence from
the model category of simplicial operads to the model category structure for
infinity-operads on the category of dendroidal sets. By slicing over the
monoidal unit, this also gives the Quillen equivalence between Segal categories
and simplicial categories proved by J. Bergner, as well as the Quillen
equivalence between quasi-categories and simplicial categories proved by A.
Joyal and J. Lurie. We also explain how this theory applies to the usual notion
of operad (i.e. with a single colour) in the category of spaces.
