[...] we will use the notion of a "type-path" [...] where ≤ has the standard lattice-theoretic interpretation: (i) If "a" is a type, then [a] is a type-path. (ii) If "a" and "b" are type-paths, and "b" ≤ "a" then ["a b"] is a type-path. - Pustejovsky & Boguraev (2004), a pag.349