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OP-0096OpenAlgebra

Andrews–Curtis conjecture

Can every balanced presentation of the trivial group be reduced to the standard one by elementary relator moves?

Source-reported statusAs of 2026-07-31Source & evidence ↓

Problem statement

Let ⟨x1,…,xn∣r1,…,rn⟩\langle x_1,\ldots,x_n\mid r_1,\ldots,r_n\rangle be a balanced presentation of the trivial group. Can its relators always be transformed to (x1,…,xn)(x_1,\ldots,x_n) using finitely many of the following moves?

  1. Invert a relator.
  2. Multiply one relator by another.
  3. Conjugate a relator by any word in the generators.

A bounded computational search that finds no sequence does not establish a counterexample. This question concerns the original conjecture; stabilized variants allowing extra generator–relator pairs are distinct.

Lean 4

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Progress & source assessment

TheoremDB’s 31 July 2026 packet reports the conjecture for thickenable balanced presentations as a known special case, citing Lackenby. Its recorded work does not resolve the unrestricted conjecture.

References
  1. [1]TheoremDB P48, Andrews–Curtis conjecture. Snapshot 31 July 2026. link

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