We give an affirmative answer to problem DJ from Fremlin's list [8] which asks whether $MA_{ω_1}$ implies that every uncountable Boolean algebra has an uncountable set of pairwise incomparable elements.
Dwight DuffusBill SandsPeter Winkler
Hongbin ChenYen-Jen ChengW. LiChia-An Liu
Hongbin ChenYen-Jen ChengWei-Tian LiChia-An Liu
Hongbin ChenYen-Jen ChengWei-Tian LiChia-An Liu