Impossibility of existence of different codirected locally-minimal trees on a plane / K. I. Oblakov. //Vestnik Moskovskogo Universiteta. Seriya 1. Matematika. Mekhanika. 2009. № 2. P. 21-25 Moscow Univ. Math. Bulletin. Vol. 64, N 2, 2009. P. 62-66].
Locally minimal graphs on a plane are considered. A simpler proof is given for the uniqueness of a globally minimal spanning tree on a plane in the general case. The proof presented here uses only local minimality of trees and is of independent interest.
Key words: locally minimal tree.