Editing Isomorphism theorems (section)

===Theorem D (groups)===

{{main | Lattice theorem}}
Let <math>G</math> be a group, and <math>N</math> a normal subgroup of <math>G</math>.
The canonical projection homomorphism <math>G\rightarrow G/N</math> defines a bijective correspondence
between the set of subgroups of <math>G</math> containing <math>N</math> and the set of (all) subgroups of <math>G/N</math>. Under this correspondence normal subgroups correspond to normal subgroups. 

This theorem is sometimes called the [[Correspondence theorem (group theory)|''correspondence theorem'']], the ''lattice theorem'', and the ''fourth isomorphism theorem''.

The [[Zassenhaus lemma]] (also known as the butterfly lemma) is sometimes called the fourth isomorphism theorem.<ref>{{cite book |last=Wilson |first=Robert A. |author-link=Robert A. Wilson (mathematician) |title=The Finite Simple Groups |date=2009 |doi=10.1007/978-1-84800-988-2 |at=p. 7 |publisher=Springer-Verlag London |isbn=978-1-4471-2527-3 |series=Graduate Texts in Mathematics 251|volume=251 }}</ref>