Tree spanner

A tree k-spanner (or simply k-spanner) of a graph $G$ is a spanning subtree $T$ of $G$ in which the distance between every pair of vertices is at most $k$ times their distance in $G$.

References

• Handke, Dagmar; Kortsarz, Guy (2000), "Tree spanners for subgraphs and related tree covering problems", Graph-Theoretic Concepts in Computer Science: 26th International Workshop, WG 2000 Konstanz, Germany, June 15–17, 2000, Proceedings, Lecture Notes in Computer Science, vol. 1928, pp. 206–217, doi:10.1007/3-540-40064-8_20.