You can see some relative discussions in some former entries and threads, so pay attention to ask some more specific quesions that are more useful.

By the way, do you really think definition is important? Why so many significant stuff cannot be defined neighter precisely nor unprecisely? For instance: how do you define a "point"?

[此贴子已经被作者于2006-1-10 20:41:15编辑过]

哦，是论坛里的帖子的两种说法。

似乎楼主发完帖子就没有再来看过了？