Séminaire Lotharingien de Combinatoire, 93B.50 (2025), 12 pp.

Harry Richman, Farbod Shokrieh and Chenxi Wu

Principal Minors of Tree Distance Matrices (Extended Abstract)

Abstract. Suppose D is the distance matrix of a tree. Graham and Pollack showed that the determinant of D satisfies a surprising identity that depends only on the number of vertices in the given tree. We generalize this result to a combinatorial identity for the determinant of any principal submatrix of D. This new identity involves counts of spanning forests and is proved by use of potential-theoretic concepts on graphs.


Received: November 15, 2024. Accepted: February 15, 2025. Final version: April 1, 2025.

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