## 2018-12-24

I continued working through Leary & Kristiansen’s book (syntax and semantics of first-order logic).

I continued reading Peter Smith’s book. (Robinson arithmetic, $\Delta_0, \Sigma_1, \Pi_1$ formulas)

I moved over the page Understanding mathematical definitions to the Learning Subwiki (previously it was in my userspace on the Machine Learning Subwiki) and worked on it more.