Until a few years ago, the topics in my Ph.D. were unfashionable, but they are very popular today.

Until a few years ago, the topics in my Ph.D. were unfashionable, but they are very popular today.

直到几年前，我的博士学位课题还不流行，但今天却很受欢迎。

-- Benoit Mandelbrot 曼德勃罗