@article {IOPORT.05059067,
    author       = {Sagan, Bruce E. and Vatter, Vincent},
    title        = {The M\"obius function of a composition poset.},
    year         = {2006},
    journal      = {Journal of Algebraic Combinatorics},
    volume       = {24},
    number       = {2},
    issn         = {0925-9899},
    pages        = {117-136},
    publisher    = {Springer, Norwell, MA},
    doi          = {10.1007/s10801-006-0017-4},
    abstract     = {Summary: We determine the M\"obius function of a poset of compositions of an integer. In fact, we give two proofs of this formula, one using an involution and one involving discrete Morse theory. This composition poset turns out to be intimately connected with subword order, whose M\"obius function was determined by Bj\"orner. We show that, using a generalization of subword order, we can obtain both Bj\"orner's results and our own as special cases.},
    identifier   = {05059067},
}