Spanning cycles in regular matroids without minors

Catlin and Jaeger proved that the cycle matroid of a 4-edge-connected graph has a spanning cycle. This result can not be generalized to regular matroids as there exist infinitely many connected cographic matroids, each of which contains a M ∗ ( K 5 ) minor and has arbitrarily large cogirth, that do not have spanning cycles. In this paper, we proved that if a connected regular matroid without a M ∗ ( K 5 ) -minor has cogirth at least 4, then it has a spanning cycle.