| 释义 |
symmetric group For any set X, a permutation of X is a one-to-one onto mapping from X to X. The set of all of these, with composition as the operation, forms a group called the symmetric group of X, denoted Sym(X). If X has n elements, there are n! permutations of X and the symmetric group is denoted Sn. See alternating group, Cayley's representation theorem.
|