Lower-dimensional obstruction for bipartite d-degenerate graphs

Determine whether, for every integer $d\ge 3$, there exists a bipartite $d$-degenerate graph that is not pandichotomous in Euclidean dimension $d-1$.

Background

The paper proves that every dd-degenerate graph is pandichotomous in Euclidean dimension dd and on the sphere of dimension d1d-1. It also constructs, for every d2d\ge 2, a (d+2)(d+2)-degenerate bipartite graph that is not pandichotomous in Euclidean dimension dd, while the corresponding one-degree-stronger bipartite obstruction in dimension d1d-1 remains unresolved.

The authors explicitly state their belief that the answer should be positive, but no proof is supplied, so the question qualifies as an unresolved conjectural problem.

References

Given $d \geq 3$, is there a bipartite $d$-degenerate graph that is not pandichotomous in~${d-1}$? We believe that the answer to this question should be positive.

Geometric realizations of dichotomous ordinal graphs  (2503.07361 - Angelini et al., 10 Mar 2025) in Section Conclusion