Order Theory


 * /Preordered sets and posets/
 * /Upper and lower bounds/
 * /Well-ordered sets/
 * /Series-parallel order/
 * /Lexicographic order/
 * /Ordinal numbers/
 * /Chains, chain conditions, Zorn's lemma/
 * /Lattices/
 * /Total orders/
 * /The Grothendieck axioms/
 * /Continuous geometries/