The document discusses the minimal spanning tree technique and Dijkstra's algorithm. Minimal spanning tree is used to connect all points in a network with minimum total distance. It takes a fully connected graph with edge distances as input and outputs a tree that connects all nodes with minimum distance. Dijkstra's algorithm finds the shortest paths from a single source node to all other nodes in a graph. It takes a graph with edge costs as input and outputs the lowest cost path between the source and each other node.