一类4叶树的Merrifield-Simmons指标

Orderings of One Special Tree by σ-Index

令a,bij是确定的整数,且a+b11+b12+b21+b22=n.本文研究了4叶树H(a,b11,b12,b21,b22)中,其中3片叶子的顶点数均为1的4叶数的Merrifield-Simmons指标,并给出了这类4叶树的σ-指标序列.

Let α,bij be positive integers with a ＋ b11 ＋ b12 ＋ b21 ＋ b22=n. Then, the n - vertex tree that is denoted by H（α,b11,b12,b21,b22 ） . That every tree with 4 leave is of the form H（α,b11,b12,b21,b22） ~ In this paper,we investigate the σ - index of the tree H（m,n - m - 3,1,1,1）, and we obtain the orderings of this tree bytr - index.