olemus
kõiki tippe sisaldav sidusa orienteerimata graafi puu

Wiktionary:
(graph theory) a tree structure which includes all vertices of a graph

ülevaateid
https://en.wikipedia.org/wiki/Spanning_tree

https://brilliant.org/wiki/spanning-trees/

http://mathworld.wolfram.com/SpanningTree.html

https://www.cs.sfu.ca/~ggbaker/zju/math/spanning-tree.html