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Is P0^{EQ} equal to Γ2?

Determine whether the class of problems computable by constant-cost deterministic protocols with oracle access to Equality (P0^{EQ}) is exactly the class of problems with constant γ2-norm (Γ2); i.e., prove or refute P0^{EQ} = Γ2.

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Background

Prior work showed P{EQ} ⊆ Γ2 and explored the tightness of this inclusion. The authors reiterate this as one of the central open problems in the area, tied to the geometric factorization norm γ2 and Equality-oracle computation.

A resolution would settle whether Equality-oracle protocols capture precisely the γ2-behavior of matrices, bridging combinatorial and geometric perspectives in communication complexity.

References

We refer to for many other open problems regarding the complexity classes in \cref{fig:hierarchy}, and more. Is $\P_0EQ = \Gamma_2$?

Sign-Rank of $k$-Hamming Distance is Constant (2506.12022 - Göös et al., 1 May 2025) in Section 6.4 (Open Problems)