Length of a Weyl group element
In mathematics, the length of an element w in a Weyl group W, denoted by l, is the smallest number k so that w is a product of k reflections by simple roots. In particular, a simple reflection has length one. The function l is then an integer-valued function of W; it is a length function of W. It follows immediately from the definition that l = l and that l ≤ l + l.
