Research project on Dyck Paths



A Dyck path is a lattice path in the nxn square which does not pass below the diagonal. Dyck paths are one of the fundamental objects enumerated by the Catalan numbers.

Consider the partial order of Dyck paths where one path is 'less' than another if it lies below. What are the properties of this poset? (it is a graded lattice where the rank function is the area, the generating function is a q-Catalan number, can we say more?) Can you calculate its mobius function? What is the relationship of this order to other Catalan enumerated objects.
In summer of 2008 I gave this problem to a student, Jennifer Woodcock, in the M.A. for Teachers program and she produced the following manuscript.
This page was last edited November 16, 2008.