ABSTRACT
As defined by Nicholson a (noncommutative) ring is a clean ring if every element of
is a sum of a unit and an idempotent. Let
be a commutative ring with identity. We define
to be a uniquely clean ring if every element of
can be written uniquely as the sum of a unit and an idempotent. Examples of clean rings (uniquely clean rings) include von Neumann regular rings (Boolean rings) and quasilocal rings (with residue field
). A ring
is a clean ring or uniquely clean ring if and only if
is. So every zero-dimensional ring
is a clean ring, but a zero-dimensional ring
is a uniquely clean ring if and only if
is a Boolean ring.