Parking functions and noncrossing partitions.
Parking functions of types A and B.
Partitions and partially ordered sets
Planar graphs as minimal resolutions of trivariate monomial ideals.
Planar ordered sets of width two
Profile classes and partial well-order for permutations.
Promotion and evacuation.
P-sets and minimal right ideals in ℕ*
Recall that a P-set is a closed set X such that the intersection of countably many neighborhoods of X is again a neighborhood of X. We show that if 𝔱 = 𝔠 then there is a minimal right ideal of (βℕ,+) that is also a P-set. We also show that the existence of such P-sets implies the existence of P-points; in particular, it is consistent with ZFC that no minimal right ideal is a P-set. As an application of these results, we prove that it is both consistent with and independent of ZFC that the shift...