Embedding partially ordered sets into ω_ω

摘要

We investigate some natural questions about the class of posets which can be embedded into (ω_ω, ≤*). Our main tool is a simple ccc forcing notion He which generically embeds a given poset E into (ω_ω,≤*) and does this in a "minimal" way (see Theorems 9.1, 10.1, 6.1 and 9.2).