Editing Emil Leon Post (section)

==Polyadic groups==
Post made a fundamental and still influential contribution to the theory of [[n-ary group|polyadic, or ''n''-ary, groups]] in a long paper published in 1940.  His major theorem showed that a polyadic group is the iterated product of elements of a [[normal subgroup]] of a [[group (mathematics)|group]], such that the [[quotient group]] is [[cyclic group|cyclic]] of order ''n'' &minus; 1.  He also demonstrated that a polyadic group operation on a set can be expressed in terms of a group operation on the same set.  The paper contains many other important results.