Katetov functors
  We develop a theory of \emph{Katetov functors} which provide a uniform way of constructing Fraisse limits. Among applications, we present short proofs and improvements of several recent results on the structure of the group of automorphisms and the semigroup of endomorphisms of some Fraisse limits. 
Wies{\l}aw Kubi\'s, Dragan Ma\v{s}ulovi\'c
math.LO