A Problem of Tree Graph

Because of the widespread applications of tree and tree graph in computer science, we are interested in studying the tree graph. M. Farber, B. Richter and H. Shank in 1 showed that the graph τ₂ (G) is connected. The result of this paper is: graph τ₂(G) is 2-edge-connected as|V(G) ≥3, at the same time, we will show the best lower bounds about vertex number and minimum degree of graph τ₂(G).