ZHANG, Ruda December 19, 2021:  Minor edits. [f64ba1c]
ZHANG, Ruda February 05, 2020:  More on dynamical systems. [72482d6]
ZHANG, Ruda December 30, 2018:  Use dollar style math markup. [1b7036c]
Ruda Zhang August 07, 2016:  Replace tab with two spaces. [adaa87b]
Ruda Zhang June 26, 2016:  one sentence per line [e15360a]
Ruda Zhang June 26, 2016:  add category tag to wiki pages [a9b356c]
Ruda Zhang June 26, 2016:  use canonical filename and no internal H1 [eeca8ff]