[Scheme I] 24 Hours for Scheme

These notes is an introduction about schemes, mostly taken from the book of Qing Liu. It can be digested in 24 hours, with some (very) basic knowledge about sheaves. In the last page, I mentioned how scheme theory is important in arithmetic geometry: there is 1-1 correspondence between $k$-rational points of $Spec(k[x_1,...,x_n]/I)$ and $V(I)$ - the zero locus of $I$ over $k^n$, and $k$ does not need to be algebraically closed.