An extended (and unfinished) tutorial on creating pictures using the software Asymptote.
A surprisingly strong relative version of the algebraic Hartogs' lemma. [not intended for publication]
Math 130's (Elementary Functions and Calculus) notes:
Math 131 (Autumn
2011, Autumn
2012),
Math 132 (Winter
2012),
Math 133 (Spring
2012)
These notes sketch a definition for Cartier divisors in terms of rational sections rather than local data. The only source I know for this is EGA. They were originally written for a seminar on Fulton's Intersection Theory assuming knowledge of Ravi Vakil's notes on algebraic geometry.
An elementary proof of generic freeness.
The (weak) Lefschetz principle via model theory.
Notes on connectedness: first lecture, second lecture
My undergraduate thesis on tropical geometry, completed under the supervision of Eric Katz.