  The notion of free link is a generalized notion of virtual link. In the
present paper we define the group of free braids, prove the Alexander theorem
that all free links can be obtained as closures of free braids and prove a
Markov theorem, which gives necessary and sufficient conditions for two free
braids to have the same free link closure. Our result is expected to be useful
in study the topology invariants for free knots and links.
