There are several categorizations of binary relations based on which axioms they hold. These are called orders. * preorder * weak order * strict weak order * strict order * strict partial order * equivalence From the orderings a framework is built up. * strict order * weak order Examples: * subset on all sets is a preorder * => on R is a strict order * "=>" on R^2 is a antisymmetric preorder * || || (magnitude) on R^2 is a weak order