A minimum spanning tree connects every vertex in a connected weighted graph while minimizing total edge weight. It is a tree, so it contains no cycles and exactly one path connects any two vertices. The practical goal is to connect a network at minimum cost. section 4.3
Connecting major metropolitan areas
A weighted graph of 15 U.S. metropolitan areas uses distances as edge weights. The resulting tree includes Seattle–San Francisco, Los Angeles–Riverside, and Dallas–Houston, connects all 15 areas, and has total weight 5,372.

