笔者在一次课堂上偶尔提到,一个点若从极限的角度考虑可看作一个圆,即以该点为圆心、零为半径的圆,顿时引发了很多同学的争议。课后就有好学者向我来求证,“如果一个点可以看作圆的话,那这个圆是否具备圆的一般性质呢?”由于此前没有过多深入研究,便信口回答:“应该也具备的,不过就一个点而 Occasionally, I mentioned in a class. If one point is considered as a circle from the perspective of limit, a circle with radius of zero and a circle of zero radius suddenly triggered many students’ controversy. There is a good scholar to prove to me after class, ”If a point can be regarded as a circle, then does this circle have the general character of a circle?" Since there was not too much in-depth research before, I replied: Should also have, but on a point