Editing Commutative algebra (section)

===Completion===
{{Main|Completion (ring theory)}}
A [[completion (ring theory)|completion]] is any of several related [[functor]]s on [[ring (mathematics)|ring]]s and [[module (mathematics)|modules]] that result in complete [[topological ring]]s and modules. Completion is similar  to [[localization of a ring|localization]], and together they are among the most basic tools in analysing [[commutative ring]]s. Complete commutative rings have simpler structure than the general ones and [[Hensel's lemma]] applies to them.