Intermediate Borel asymptotic separation index

Determine whether there exists a locally finite Borel graph whose Borel asymptotic separation index is strictly greater than one but finite.

Background

The paper defines the Borel asymptotic separation index as a parameter measuring the number of smooth or finite-class pieces needed to control bounded neighborhoods in a Borel graph. It proves that finite Borel asymptotic dimension implies asymptotic separation index at most one. The authors leave unresolved whether finite values strictly between one and infinity can occur.

References

It is an open question whether there is any locally finite Borel graph G with 1 < \asi_B(G) < \infty.

Hyperfiniteness of bounded-to-one actions of commutative monoids  (2608.18439 - Shinko et al., 19 Aug 2026) in Section 3, immediately after Lemma 3.5