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CounterexampleConstruction: AI-generatedVerification: AI-generatedprecheck passjudge pass (gpt-5.6-terra)audited 2026-09-12
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 domino family where matching fails unless one illegally permutes symbols inside a tile

Statement refuted

PCP permits one to reorder the symbols inside a chosen domino before concatenating it.

Facts & Assumptions

Given: The one-domino PCP instance (ab,ba).

[L1]

The companion false statement says PCP would allow internal symbol reordering, by FALSE: PCP permits reordering symbols inside a domino.

Counterexample

technique · direct
1.1given

Consider the one-domino instance (ab,ba). If internal permutation were allowed, the bottom word ba could be rearranged to ab, so one use of the domino would look like a match.

2.1step 1.1

In actual PCP, only whole dominoes may be concatenated. Using the unique tile k≥1 times gives top word (ab)k and bottom word (ba)k, whose first symbols differ. So the instance has no legal match.

3.1L1step 2.1∎

Therefore this instance refutes the statement. It is exactly the concrete counterexample recorded abstractly in [L1].

Depends on

Used by

Nothing in the library uses this result yet.

Dependency tree · two levels

2 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.