OneIdentity

Usage

• OneIdentity is an attribute that can be assigned to a symbol f to indicate that f[x], f[f[x]], etc. are all equivalent to x for the purpose of pattern matching.

Notes

• OneIdentity has an effect only if f has attribute Flat.

• Functions like Plus and Times have the attribute OneIdentity.

• The fact that Times has attribute OneIdentity allows a pattern like n_. x_ to match x.

• See Section 2.3.7 and Section 2.6.3.

• See also: Flat, Nest.

• New in Version 1.