2-树不相似特征定理的一个证明

A PROOF OF DISSIMILARITY CHARACTERISTIC THEOREM FOR 2-TREES

2 -树不相似特征定理就是对于任何具有q 类不相似线 ,r 类不相似格 ,s1类恰好具有两条相似线的不相似格 ,s2 类具有三条相似线的不相似格的 2 -树 ,其中s =s1+2s2 ,有q +s- 2r =1.F .Harary利用构造的方法说明了这一定理 ,但并未给出严格证明 ,这里将给出这一定理的一个证明 .

Dissimilarity characteristic theorem for 2-tree is for any 2-tree with q * dissimilar lines, r * dissimilar cells, s 1 dissimilar cells with exactly two similar lines, s 2 dissimilar cells with all three similar lines, where s=s 1+2s 2 , then q *+s-2r *=1 .Harary presented this theorem, but he didn't give its strict proof.In this note, a proof of this theorem is presented.