Homework of Algebraic Geometry

*In this file, I gather some classic Counterexamples in AG. It will keep updating.*

sheaf and scheme

Hartshorne: GTM52
ii.1: 1.2, 1.3, 1.7, 1.9, 1.10, 1.12, 1.14, 1.21, 1.22

Atiyah: CA
Chapter 2: direct sum.
Atlas of Spec$\mathbb{Z}[x]$

Why is Hurewicz Map a Natural Transformation?