DM
2002
13 years 4 months ago
2002
For each prime p, we construct an infinite antichain of matroids in which each matroid has characteristic set {p}. For p = 2, each of the matroids in our antichain is an excluded m...
COMBINATORICS
2000
13 years 4 months ago
2000
We constructively prove that the partially ordered set of finite permutations ordered by deletion of entries contains an infinite antichain. In other words, there exists an infini...