Case 1. If all the removed edges are incident with the same vertex, say vn.
Since k n − 3, then vn is adjacent to a vertex in G, say vn−1. Consider the
tree v1v2 . . . vn−2vn−1vn−1vn. The degrees of the vertices in G and in T are as
follows: degT (v1) = degT (vn) = 1 and degT (v2) = . . . degT (vn−1) = 2. However:
degG(vn) = n − 1 − k 2, degG(vn−1) = n − 1 and for all 2 i n − 2, we
have degG(vi) n − 2. This proves that T does not preserve the degree of any
vertex in G