… cf functors from a given category to the category of groups. The objects are the covariant
functors, the maps between the objects are the netural transformaticns betreen the functors, We …

… , involving heavily the entire theory of functors and the construction of … the theory of categories
of cyclic modules into a theory about … We then return to the functor theory to cut down to the …

… which is natural not only as functors of the S-module Af, but also as functors of the variable
p. … exact functors. Now if C is a retract of D in Cat, then SF is a retract of OP via exact functors, …

… role played in category theory by the functor evaluation and the … me many unpublished facts
of Category Theory and are directly … of completeness and especially unification of the theory. …

… Green functors have in some ways a fighter structure than Mackey functors, but we will
not describe their theory in detail here. Fuller accounts of recent theory may be found in [58,59] …

… field theory to construct a very simple but still non-trivial example of a field theory with
defects… ), lattice topological field theory with defects (Theorem 3.8), and the centre functor (Theorem …

… present the analogous theory for infinite loop spaces. We define a functor Tf from pointed
spaces to topological monoids whose rale is analogous to that of the free monoid functor in the …

… between algebraic K-theory and the homotopy theory of spectral Mackey functors. We
show that spectral Mackey functors can be described as excisive functors from a certain “derived …

… , determines an algebraic theory, and conversely every algebraic theory has such … theories
we will understand a functor which preserves products and takes 1 into 1. Algebraic theories …

… functors in the spirit of representation theory, and it emerges that there are great similarities
with the representation theory … of the existing theory we will refer to the Mackey functors as JK(…