Nerves of convex sets: classification for remaining parameters

Classify the complexity of recognizing whether a given simplicial complex is the k‑skeleton of the nerve of c‑dimensional convex sets in ℝ^d for the parameter combinations not covered by current results.

Background

The nerve realizability problem depends on three parameters (k,c,d). For several ranges (e.g., k ≥ d, c ∈ {d−1,d}), ER-completeness is known. Some combinations are always realizable, making their recognition trivial.

The authors explicitly note that the remaining parameter regimes have not been settled.

References

All remaining parameter combinations are still open.

The Existential Theory of the Reals as a Complexity Class: A Compendium (2407.18006 - Schaefer et al., 25 Jul 2024) in Compendium — Problem 'Nerves of Convex Set(s)'