 In algebraic QFT, an algebra of observables is associated with bounded regions of Minkowski spacetime (and unbounded regions including all of spacetime by way of certain limiting operations) that are required to satisfy standard axioms of local structure: isotony, locality, covariance, additivity, positive spectrum, and a unique invariant vacuum state. The resulting set of algebras on Minkowski spacetime that satisfy these axioms is referred to as the net of local algebras. It has been shown that special subsets of the net of local algebras – those corresponding to various types of unbounded spacetime regions such as tubes, monotones (a tube that extends infinitely in one direction only), and wedges – are type-III factors. Of particular interest for the foundations of physics are the algebras that are associated with bounded spacetime regions, such as a double cone (the finite region of intersection of a forward and a backward light cone). As a result of work done over the last thirty years, local algebras of relativistic QFT appear to be type III von Neuman algebras see Halvorson (2007, pp. 749–752) for more details.