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math.CO2019
The diameter and radius of radially maximal graphs
Pu Qiao, Xingzhi Zhan
A graph is called radially maximal if it is not complete and the addition of any new edge decreases its radius. In 1976 Harary and Thomassen proved that the radius and diameter…
math.CO2019★ 1 cited
Relation between the number of leaves of a tree and its diameter
Pu Qiao, Xingzhi Zhan
Let denote the minimum possible number of leaves in a tree of order and diameter In 1975 Lesniak gave the lower bound for …
math.CO2019
Pairs of a tree and a nontree graph with the same status sequence
Pu Qiao, Xingzhi Zhan
The status of a vertex in a graph is the sum of the distances between and all other vertices. Let be a connected graph. The status sequence of is the list of the st…