Alphabeta Math
CounterexampleConstruction: Literature-sourcedVerification: AI-generatedSession-authored (Fable 5 assisted)precheck passjudge pass (gpt-5.6-terra)audited 2026-08-27
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.

Z^2 is not hyperbolic

Statement refuted

The page proves that not every finitely generated group is hyperbolic; the standard witness is Z2.

Facts & Assumptions

Given: The free abelian group Z2.

[L1]

Free abelian groups of rank at least two are not hyperbolic (Free abelian groups of rank at least two are not hyperbolic).

Counterexample

technique · direct
1.1

The group Z2 is free abelian of rank 2.

given
2.1

Therefore [L1] shows that Z2 is not hyperbolic, providing the required counterexample.

L1step 1.1

Depends on

Used by

Nothing in the library uses this result yet.

Dependency tree · two levels

5 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