Decision problems for two‑relator groups
Determine the decidability of the word problem, the conjugacy problem, and the isomorphism problem for finitely presented two‑relator groups.
References
The word problem, conjugacy problem, and isomorphism problem are all open for two-relator groups.
— The theory of one-relator groups: history and recent progress
(2501.18306 - Linton et al., 30 Jan 2025) in Section 8.4 (Two‑relator groups)