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.
Every symmetric submodel satisfies Choice
Statement
False: full generic extensions of choice models preserve AC, but hereditarily symmetric names may omit enumerations and choice functions. The basic Cohen model and the corrected socks model are transitive ZF countermodels.
Facts & Assumptions
Given: The hypotheses, objects, and conventions in the Statement.
Generic extensions satisfy ZF and preserve ground-model Choice says that a full generic extension of a ZFC ground satisfies ZFC.
The basic Cohen model fails well-orderability and AC gives a symmetric inner model with an infinite Dedekind-finite set of reals and hence failure of AC.
An atom-free symmetric model has countable pairs without choice gives a symmetric inner model in which choice already fails for a countable family of pairs of sets of reals.
Counterexample
Let be generic for the basic Cohen forcing over a ZFC ground. By F1 the ambient satisfies AC. The hereditarily symmetric interpretation , however, contains the invariant set while every proposed enumeration is moved by a finite-support transposition. By F2, . Thus directly refutes the universal statement.
The socks construction sharpens the same failure mode: the indexed pair family is invariant, while a swap outside a proposed choice name's finite support exchanges its selected mate. Hence the family lies in the symmetric model but no choice function does.
The failed inference is therefore . Transitivity and satisfaction of ZF pass to the symmetric interpretation by its separate model theorem; AC does not.
Depends on
Used by
Nothing in the library uses this result yet.
Dependency tree · two levels
16 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, §§10.3–10.4, pp. 48–51 (standard reference, not scraped)