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.
Identity and successor in a normal ultrapower
Example
In ZFC, assume U is a normal measure on kappa and write Scott classes through their transitive collapse. For every alpha<kappa,
Facts & Assumptions
Given: ZFC. Computed constant, identity and successor classes and verified the strict bound from all coordinate successors remaining below kappa.
Measurability, normal measures and elementary embeddings: Normality identifies the collapsed identity class with kappa.
The critical point of a measurable ultrapower: Constant ordinal classes below kappa are fixed.
Los schema for the universe ultrapower: Universe Los transfers each fixed first-order membership formula to the Scott ultrapower and hence through its collapse.
Verification
F2 gives [c_alpha]=j(alpha)=alpha for alpha<kappa; F1 gives [id]=kappa. At every coordinate xi, the ordinal xi+1 is the set xi union {xi}, namely the successor of xi. F3 transfers this fixed defining formula, so the collapsed class of xi maps to xi+1 is the successor of [id], exactly kappa+1.
An infinite cardinal kappa is a limit ordinal: any infinite successor ordinal beta+1 is equinumerous with beta by shifting a countably infinite subset, so cannot be an initial ordinal. Therefore xi+1<kappa for every xi<kappa. The successor representative takes its values in kappa at all coordinates, so its class belongs to j(kappa) by coordinate membership. Step 1.1 identifies this member with kappa+1, proving the strict inequality.
Depends on
Used by
Nothing in the library uses this result yet.
Dependency tree · two levels
11 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
- Marks Lemma 23.8 and Exercise 23.9 p.94 (standard reference, not scraped)