漸近仮定：
\lim_{n{\to}\infty}{{\tau}_n{\Rightarrow}}d(x,x_{nn}){\rightarrow}0
のもとで、

\frac{1}{2}{\epsilon}^*{\leq}{\epsilon}_{2NN}{\leq}{\epsilon}_{4NN}{\leq}...{\leq}{\epsilon}^*{\leq}...{\leq}{\epsilon}_{3NN}{\leq}{\epsilon}_{NN}{\leq}2{\epsilon}^*

が成り立つ。