DM
2002
13 years 10 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 10 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...