Characterizing minimally image-extendable bipartite graphs

In this paper, it is proved that let image be a bipartite graph with bipartition image and with a perfect matching image, let image be an image-extendable graph, then image is minimally image-extendable if and only if, for any two vertices image and image such that image, there are exactly image internally disjoint image-alternating paths image such that image starts and ends with edges in image.