Gaunt-closure of the ∞-categorical Gray tensor product

Establish that for any pair of gaunt ω-categories A and B, the ∞-categorical Gray tensor product A ⊗ B in Cat_(∞,∞) is again gaunt; equivalently, show that the ∞-categorical and strict Gray tensor products coincide on the full subcategory Gaunt ⊂ Cat_(∞,∞) (or Gaunt ⊂ StrCat_ω).

Background

The paper develops Campion’s ∞-categorical Gray tensor product ⊗ on (∞,∞)-categories and compares it with the strict Gray tensor product ⊗str on strict ω-categories. The authors work extensively with the full subcategory Gaunt of strict ω-categories that are simultaneously univalent and strict, and many constructions are phrased via pasting diagrams in Gaunt.

A key technical assumption that would simplify computations is the agreement of the ∞-categorical tensor product with the strict tensor product on Gaunt. This agreement is equivalent to the closure of Gaunt under ⊗ in the ∞-categorical setting; proving it would guarantee that tensor products of gaunt ω-categories remain gaunt and legitimize strictly diagrammatic calculations for objects like θ_p ⊗ θ_q. The authors note that this equivalence is expected but not yet proven.

References

It is expected, but not proven in, that the \infty-categorical and strict-categorical tensor products agree when restricted along $Gaunt \subset Cat_{(\infty,\infty)}$ or $Gaunt \subset StrCat_{\omega}$. ByThm.~3.14 this is equivalent to the assertion that the \infty-categorical tensor product of two gaunt \omega-categories is again a gaunt \omega-category (also seeAssumption~3.5(3)), which is unknown at the time of writing.

How to build a Hopf algebra  (2508.16787 - Johnson-Freyd et al., 22 Aug 2025) in Warning (Gray Gaunt), Subsection 2.3: The lax tensor product ⊗ on (∞,∞)-categories