On the existence of large antichains for definable quasi-orders

2018/08/27 by Miller, Benjamin D., Vidnyánszky, Zoltán
#03E15 #28A05 #FOS: Mathematics #Logic (math.LO)

paper · doi:10.48550/arxiv.1808.09056

Abstract

We generalize Harrington-Marker-Shelah's Dilworth-style characterization of the existence of non-empty perfect antichains to co-analytic quasi-orders, establish the analogous theorem at the next definable cardinal, and consider generalizations beyond the first level of the projective hierarchy.

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