Isomorphism between the three-dimensional rigidity and cofactor matroids

Determine whether the generic three-dimensional rigidity matroid \(\mathcal{R}_3\) is isomorphic to the \(C_2^1\)-cofactor matroid.

Background

The unresolved double circuit property for R3\mathcal{R}_3 may be approachable through the closely related C21C_2^1-cofactor matroid. The paper notes that the rank function of the cofactor matroid has recently been characterized.

An isomorphism between the two matroids would transfer structural information between the cofactor and rigidity settings and could provide a route toward resolving the three-dimensional double circuit problem.

References

It is conjectured that this matroid is isomorphic to $_3$ and recently the rank function of this matroid has been characterised .

$k$-fold circuits and coning in rigidity matroids  (2508.18838 - Hewetson et al., 26 Aug 2025) in Section 7, concluding remark 1