令T(n,i)表示顶点数为n且匹配数为i的所有树的集合,研究了T(4n-1,2n-1)中哪些树的第二个最大特征值等于1/2[n+1+(n+1)2-8]的一个猜想。此外,还进一步得到了T(4n-1,2n-1)中树的第二个最大特征值的3个新的上界,并且确定了达到上界的所有的树。
A conjecture about whose second largest eigenvalue of trees in T(4n-1,2n-1) be equal to 12[n+1+(n+1)2-8] is made,where T(n,i) represents the set of all trees with vertex number n and matching number i.Moreover,three new upper bounds of the second largest eigenvalue of trees in T(4n-1,2n-1) were obtained,and all trees corresponding the upper bounds were determined.