Arthur Cayley's On the theory of groups, as depending on the symbolic equation θn = 1 (1854) gives the first abstract definition of a finite group.
Στο έργο του Arthur Cayley, On the theory of groups, as depending on the symbolic equation θn = 1 (1854) δίνεται ένας πρώτος αφηρημένος ορισμός της πεπερασμένης ομάδας.