Let P be the ordered set of isomorphism types of finite ordered sets (posets), where the ordering is by embeddability. We study first-order definability in this ordered set. We ...
Any model of ZFC + GCH has a generic extension (made with a poset of size 2) in which the following hold: MA + 20 = 2+ there exists a 2 1-well ordering of the reals. The proof con...
For stable marriage (SM) and solvable stable roommates (SR) instances, it is known that there are stable matchings that assign each participant to his or her (lower/upper) median ...