Theorem 4.1 An edge e of a graph G is a bridge if and only if e lies on no cycle of G. tree:无环连通图 推论：Every edge in a tree is a bridge 问题1g 从应用的角度看。上述推论有何指导意义？Theorem 4.1 An edge e of a graph G is a bridge if and only if e lies on no cycle of G. 推论：Every edge in a tree is a bridge tree：无环连通图