Let a divisor of
be called a 1-ary (or unitary) divisor if
(i.e.,
is relatively prime to
). Then
is called a
-ary divisor of
, written
, if the greatest
common
-ary
divisor of
and
is 1 (Cohen 1990).
In this notation,
is written
,
and
is written
.
is an infinitary
divisor of
(with
)
if
.
Suryanarayana (1968) unfortunately uses a different and conflicting definition.