In mathematics, pointless topology (also called point-free or pointfree topology, or locale theory) is an approach to topology that avoids mentioning points, and which the lattices of open sets are the primitive notions in it. Ehresmann's approach involved using a category whose objects were complete lattices which satisfied certain distributive law and it's morphisms where maps which preserved finite meets and arbitrary joins. He called such a lattices "local lattices", others like Dowker called it frame to avoid ambiguity with other notions in lattice theory.