# Normal form

The term**is used in a variety of contexts. Many of the uses in mathematics are special cases of a single situation, looked at abstractly: within an equivalence class one specifies a**

*normal form**representative element*, which is in a simplest or most manageable or otherwise tidiest and most desirable form, in terms of structure or syntax. A little more loosely, an equivalence class might contain several examples of such special, distinguished elements. For example, the

*Jordan normal form*under similarity of matrices (link below) may mean any suitable block matrix in similarity class, and in the general case there can be several such.

In Boolean algebra:

In Computation Theory and Languages: In relational database theory- first normal form
- second normal form
- third normal form
- fourth normal form

In linear algebra:

In musical set theory:- the normal form of a pitch or pitch class set, which is the order that occupies the smallest possible span and is stacked leftmost.

See also: canonical form