How statement and proof provenance work
The first chip identifies the source of the statement or construction; the second identifies the source of its local proof or verification.
- Literature-sourced: the exact statement appears in a cited source; only wording and notation differ.
- AI-adapted: a semantically identical restatement of literature-sourced material, modulo indexing, notation, and boundary cases adopted by the library.
- AI-generated: a genuinely novel statement formulated by AI, with no source for the claim itself.
These labels describe origin, not correctness: citations and verification chips remain separate evidence.
PFA implies MA(aleph-one) and the Suslin Hypothesis
Statement
In ZFC plus PFA, holds and the Suslin Hypothesis holds.
Facts & Assumptions
Given: PFA.
PFA supplies a filter meeting any family of at most dense sets in a proper forcing. The Proper Forcing Axiom
Every ccc forcing is proper. Ccc and countably closed forcings are proper
rules out Suslin trees. MA(aleph-one) eliminates Suslin trees
A Suslin line exists exactly when a Suslin tree exists; consequently SH is equivalent to nonexistence of a Suslin tree. Kurepa equivalence
The supplier theorems work in ZFC and propagate their stated uses of AC. The Axiom of Choice
Proof
Let be ccc and let be a family of at most dense subsets of . By F2, is proper, so F1 gives a filter meeting all members of . This is precisely .
Applying F3 to step 1.1 shows that no Suslin tree exists.
By F4, nonexistence of Suslin trees is equivalent to nonexistence of Suslin lines, which is the Suslin Hypothesis. Thus PFA implies both asserted conclusions. No value of the continuum was used.
Depends on
Used by
Dependency tree · two levels
24 results within two dependency steps of this one, each drawn at its shortest distance from it. An arrow runs from a result to what uses it, so the chart reads left to right and ends at this result, which carries a heavier outline. Every node is a link to that result. Click elsewhere on the chart to enlarge it.
Sources
- Karagila, Forcing & Symmetric Extensions, Sections 7-8 (standard reference, not scraped)