I’m a *graduated* student from Nankai University. My main interesting is in category theory, algebraic geometry and number theory. I’ve held a reading group for couple of years and written lots of math notes. This site is planed to put them and post some short essays. It is welcome for anyone to point out my mistakes.

**Remarks:** The name “Gau, Syu” is the old-fashion pinyin of my name 高煦. In standard pinyin, my family name should be written as “Gao” and given name as “Xu”.