Tuesday, April 03, 2007

A problem in a JCSS paper

不曉得我是不是有搞錯,不過目前為止這篇 paper 真的有不少錯誤。就底下的論述而言

For any positive integer n, if x \geq (n-1)/2, then \floor(x) \geq x(1-1/n).

我找到一個反例如下:

Let n = 101, so x \geq (101-1)/2 = 50
Then let x = 50.9, we have \floor(x) = 50 ....... (*)
x(1-1/n) = 50.3960396 ....... (**)

(*) is not greater than or equal to (**).


天啊,我得好好再 check 這篇 paper....

No comments: