1. The document discusses various types of stochastic processes that can be used to model stock prices, including discrete and continuous time processes. 2. It states that continuous time, continuous variable processes are most useful for valuing derivatives. These include Wiener processes and Ito processes. 3. Ito's lemma is described as a tool that allows determining the stochastic process followed by a function of a variable that itself follows a stochastic process, which is important for analyzing derivative securities.