跨树以查找遍历图的最小成本。一棵生成树 T 的无向图 G 是包括所有的是一棵树的 G thevertices 的子图。一般情况下，图可能有几个生成树，但未连接图中将不包含生成树 （但请参见跨越森林下面）。如果所有边缘 G 也跨越边缘树 G T 则 G 是一棵树，是与 T 相同 （即，一棵树上有一棵独特的生成树和它本身就是
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spanning tree fourb.m gs.m lincomb.m mydet.m rot2d.m span.m transmat.m
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