The maximum number of edges in minimal matching covered graphs
A connected graph $G$ with at least two vertices is {\em matching covered} if each of its edges lies in a perfect matching. A matching covered graph is {\em minimal} if the removal of any edge results in a graph that is no longer matching covered. Lov\'asz and Plummer [J. Combin. Theory, Ser. B 23 (1977) 127--138] prov...