ABSTRACT
In his celebrated work [Mar’], A.A. Markov has described the theorem about necessary and sufficient conditions for braids to represent isotopic links. However, his proof did not contain all rigorous details. He left this problem to N.M. Weinberg, who died soon after his first publication on the subject [Wei]. The first published rigorous proof belongs to Joan Birman, [Bir]. The newest proofs of Markov’s theorem can be found in [Tra] and in [BM].
