Stolz-Cesàro theorem

L’Hôpital’s rule: for functions \(f\) and \(g\) which are differentiable on \(I \backslash\{c\}\) , where \(I\) is an open interval containing \(c\), if [more]

Snapshot backup

This is a method of backup that I invented many years ago and used at workplace. I think it is quite useful because it abused the nature of hard links in UNIX. [more]