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.
A generic filter belongs to its ground model
Statement
False claim, conditional on a supplied externally countable transitive ZF model M: every M-generic filter for a forcing notion in M belongs to M.
Facts & Assumptions
Given: ZF conditional on the supplied countable transitive model and enumeration. Cohen splitting gives atomlessness, a generic exists by least-index recursion, and its failure to be ground-model follows both from the dense-complement theorem and the real-union calculation.
Atomless generic filters are not in the ground model: An M-generic filter on atomless forcing is not in M.
Generics over countable transitive models in ZF: A supplied external enumeration produces an M-generic filter through any condition in ZF.
Cohen-name valuation and dense-set meeting: For Cohen forcing the union of a generic filter is a total binary sequence different from every ground-model binary sequence.
Refutation
In the supplied M use with extension order. Its finite sequences and order are the actual ones by transitivity and actual omega. Below each s the sequences formed by appending 0 and 1 are incompatible, so P is atomless. Apply F2 through the empty condition to obtain an M-generic filter G.
F1 now gives , refuting the universal claim. Equivalently, F3 makes a binary sequence not in M, whereas G in M would put its actual union in M by internal Union and transitivity. The counterexample remains conditional on the supplied model; ZF does not here prove that such a model exists. Singleton forcing still has a ground-model generic filter, so the false claim is not replaced by an unconditional assertion about all forcing orders.
Depends on
Used by
Nothing in the library uses this result yet.
Dependency tree · two levels
6 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 Theorems 1.13–1.14 p4; one-point forcing boundary (standard reference, not scraped)