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RemarkRemark: Literature-sourcedProof: Not applicablePipeline-generatedjudge pass (gpt-5.6-terra)audited 2026-09-14
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.

Magidor and extender Prikry forcing are orientation, not substitutes

Remark

Ordinary Prikry forcing uses one normal measure and, as Prikry forcing preserves every cardinal proves, changes the cofinality of its measurable cardinal to ω without collapsing cardinals. Two related families explain the surrounding landscape but supply none of the later Gitik arguments on this page.

Magidor forcing. With an appropriate coherent sequence of measures and the corresponding Mitchell-order hypothesis, Magidor forcing can change the cofinality of the large cardinal to a prescribed smaller regular cardinal. The word “prescribed” does not mean that every regular target is available from one fixed measurable-cardinal hypothesis: the measure sequence must be long enough for the chosen target. Poveda Ruzafa, Section 7.1, states this parameter and hypothesis explicitly.

Extender-based Prikry forcing. Extender-based variants coordinate many measure projections rather than using the single normal measure of ordinary Prikry forcing. Merimovich's Prikry on Extenders, Revisited is a concrete example: its forcing changes cofinality to ω without adding bounded subsets while also controlling the power set. “Extender-based” is therefore a family label, not a claim that every such forcing has one common cofinality or preservation profile.

Neither family is a substitute for the construction below. Gitik's target here uses a proper class of strongly compact cardinals, fine complete ultrafilters as in Fine measures, strong compactness and supercompactness, a definable proper-class forcing relation, and a finite-support symmetric submodel. No later item cites this remark as a proof of any of those features.

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Dependency tree · two levels

15 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