In mathematics, a uniform tree is a locally finite tree which is the universal cover of a finite graph. Equivalently, the full automorphism group G = A u t ( X ) {\displaystyle G=Aut(X)} of the tree, which is a locally compact topological group, is unimodular and G / X {\displaystyle G/X} is finite. Also equivalent is the existence of a uniform X-lattice in G {\displaystyle G} . For a graph G {\displaystyle G} which contains no cycles, G {\displaystyle G} is its own uniform tree. If G {\displaystyle G} contains at least 1 cycle, its uniform tree is an infinite tree. Leighton's Graph Covering Theorem states that any two finite graphs that share a common covering must also share a common finite covering. Walter D. Neumann expanded on this in 2011, proving any two graphs that have a common covering necessarily have the same universal covering. This means that every uniform tree corresponds to a unique family of finite graphs.
See also Covering graph
Sources Bass, Hyman; Lubotzky, Alexander (2001), Tree Lattices, Progress in Mathematics, vol. 176, Birkhäuser, ISBN 0-8176-4120-3 Neumann, Walter D. (2011). "On Leighton's graph covering theorem". Groups, Geometry, and Dynamics. 4 (4): 863–872. arXiv:0906.2496. doi:10.4171/ggd/111.


