出典:Wiktionary
出典:Wikipedia
出典:『Wikipedia』 (2011/05/27 18:03 UTC 版)
In mathematics, the braid group on n strands, denoted by Bn, is a group which has an intuitive geometrical representation, and in a sense generalizes the symmetric group Sn. Here, n is a natural number; if n > 1, then Bn is an infinite group. Braid groups find applications in knot theory, since any knot may be represented as the closure of certain braids.