  We give a definition of the Gray tensor product in the setting of scaled
simplicial sets which is associative and forms a left Quillen bifunctor with
respect to the bicategorical model category of Lurie. We then introduce a
notion of oplax functor in this setting, and use it in order to characterize
the Gray tensor product by means of a universal property. A similar
characterization was used by Gaitsgory and Rozenblyum in their definition of
the Gray product, thus giving a promising lead for comparing the two settings.
