Square and Delta reflection

2016/02/03 by Laura Fontanella, Fontanella, Laura, Yair Hayut +1
Mathematics · #FOS: Mathematics #Logic (math.LO) #math.LO

paper · pdf · doi:10.48550/arxiv.1602.01264

arxiv created 2016/02/03 · arxiv updated 2016/02/04

Abstract

Starting from infinitely many supercompact cardinals, we force a model of ZFC where ℵ_ω²+1 satisfies simultaneously a strong principle of reflection, called Δ-reflection, and a version of the square principle, denoted \square(ℵ_ω²+1). Thus we show that ℵ_ω²+1 can satisfy simultaneously a strong reflection principle and an anti-reflection principle.

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