A. D. Elmendorf and M. A. Mandell
Multiplicative structure in infinite loop space theory
We extend the K-theory functor constructed in our previous paper
(Rings, modules, and algebras in infinite loop space theory,
Advances in Mathematics 205 (2006) 163-228) to the bicomplete
symmetric monoidal closed category of based (symmetric)
multicategories, to which our previous source category of
permutative categories and lax morphisms maps fully and
faithfully.