Andrews–Curtis conjecture with stabilizations

Determine whether every balanced presentation of the trivial group can be transformed into a trivial balanced presentation using relator permutations, relator inversion, multiplication of one relator by another, conjugation of a relator by a generator word, and stabilization by adjoining a generator together with a relator equal to that generator.

Background

The Andrews–Curtis conjecture with stabilizations (ACCS) is presented as a consequence of Zeeman’s collapsibility conjecture. It asserts that balanced presentations of the trivial group can be simplified to the trivial balanced presentation through specified elementary operations, including stabilization.

The paper establishes the equivalence of ACCS and ZCC after proving the reduction from arbitrary contractible two-polyhedra to standard ones. Since ZCC remains unresolved, this equivalent algebraic conjecture also remains unresolved.

References

It is well known that this conjecture (which we abbreviate as ZCC) implies the Andrews--Curtis conjecture with stabilizations (ACCS), which states the following. Let~$\langle a_1,\ldots,a_n\,|\,r_1,\ldots,r_n\rangle$ be a balanced presentation of the trivial group. Then it can be transformed into a trivial balanced presentation by a sequence of operations of the following kinds:

On Zeeman's collapsibility conjecture for non-standard polyhedra  (2608.23331 - Dynnikov, 24 Aug 2026) in Conjecture 2, Section 1 (Introduction)