Define mapping spaces for ruptured simplicial sets

Develop a rigorous construction of the mapping space Map(X, Y) for ruptured simplicial sets X and Y by specifying a canonical ruptured structure on the standard simplices Δ[n] and proving that this yields a well-defined object in the category of ruptured simplicial sets (rsSet), including verification that coherence is preserved and gap-witnessed horns are mapped appropriately.

Background

The paper extends simplicial sets to ruptured simplicial sets that track coherent simplices and gap-witnessed horns. Standard constructions like products are developed, but the mapping-space construction is only outlined.

The authors note that defining Map(𝒳, 𝒴) requires choosing a canonical ruptured structure on the standard simplices and proving that the resulting mapping space lives naturally in the category of ruptured simplicial sets, which is deferred to future work.

References

The notion of mapping space extends to the ruptured setting, but the full development requires care. The details—particularly the canonical ruptured structure on #1{n} and the verification that \mathrm{Map}(\mathcal{X}, \mathcal{Y}) is well-defined in \mathbf{rsSet}—are deferred to future work.

Open Horn Type Theory  (2512.24498 - Poernomo, 30 Dec 2025) in Remark [Mapping Spaces], Section "Constructions on Ruptured Simplicial Sets", Chapter "Ruptured Simplicial Sets"