A universal Aronszajn line

Justin Tatch Moore
2009 Mathematical Research Letters  
The purpose of this note is to define an Aronszajn line η C and prove that under the assumption of PFA it is universal for the class of Aronszajn lines. Moreover η C can be easily described in terms of a fixed Countryman type C: it is the direct limit of the finite lexicographic products of the form C × (−C) × . . . × (±C).
doi:10.4310/mrl.2009.v16.n1.a12 fatcat:tctb6wi4u5bt7euubkk6wg4fb4