STA 447/2006: Stochastic Processes

Wenlong Mou, Department of Statistical Sciences, University of Toronto, Winter 2025

Schedule

lecture topic book chapteres notes
01/08 introduction, Markov definitions and transition probabilities, recurrent and transient states, recurrent state theorem Rosenthal 1.1 – 1.5 Lecture 1
01/15 recurrence of multi-dimensional random walks, f-expansion, gambler's ruin, communicating states and irreducibility, recurrence equivalence theorems Rosenthal 1.5 – 1.7 Lecture 2
01/22 reducible Markov chains, stationary distribution, reversible Markov chains, criteria for non-existence of stationary distribution, periodicity Rosenthal 2.1 – 2.3, Lawler 1.5 Lecture 3
01/29 Markov chain convergence theorem, stationary measure of recurrent Markov chains, mean recurrence time and positive recurrence, strong law of large numbers for Markov chains Rosenthal 2.4, 2.5, 2.8, Durrett 1.7 Lecture 4
02/05 Midterm exam #1, additional topics: strong law of large numbers for Markov chains, applications to MCMC Durrett 1.7, Rosenthal 2.6 Lecture 5, Solutions
02/12 Martingales and stopping times, optional stopping theorems and their proofs, application to gambler's ruin problem Rosenthal 3.1, 3.2, Lawler 5.3 Lecture 6
02/26 Uniform integrability, Wald's theorem, Doob's maximal inequality, martingale convergence theorem and upcrossing inequality Rosenthal 3.3, Lawler 5.4 – 5.6 Lecture 7
03/05 L^1 and L^p convergence of martingales, Brownian motion definitions and basic properties, continuous-time OST and applications, reflection principle Rosenthal 4.1, Lawler 5.5, 5.6, 8.2, 8.3 Lecture 8
03/12 Midterm exam #2, additional topics: branching process, Doob's martingale with applications to posterior distributions Rosenthal 3.6, Lawler 5.5 Lecture 9, Solutions
03/19 stochastic integration, Itô's formula, quadratic variation Lawler 9.1, 9.2, 9.3 Lecture 10
03/26 generalization of Itô's formula, applications to PDE problems Lawler 9.4, 9.7, 8.4, 8.5 Lecture 11
04/02 Poisson process and Poisson point processes, continuous-time discrete-space Markov chains Rosenthal 4.3, 4.4 Lecture 12

Recommended practice questions

  • Week 1: Rosenthal 1.3.9, 1.4.8, 1.5.4, 1.5.9

  • Week 2: Rosenthal 1.5.13, 1.5.14, 1.6.20, 1.6.21, 1.6.25, 1.7.12

  • Week 3: Rosenthal 2.1.3, 2.4.13, 2.4.14, 2.4.15, 2.4.16, Lawler 1.7, Durrett 1.72

  • Week 4: Rosenthal 2.4.18, 2.4.20, Durrett 1.70, 1.73, 1.74, 1.75, (if interested, there is a book on Markov chain convergence speeds)

  • Week 5: (midterm exam 1)

  • Week 6: Rosenthal 3.1.1, 3.2.3, 3.2.8, 3.2.9, 3.2.10, 3.2.11, Lawler 5.4, 5.8, 5.9 (correction)

  • Week 7: Rosenthal 3.5.6, 3.5.7, Lawler 5.13, 5.15, Durrett 5.2, 5.6

  • Week 8: Durrett 5.2, 5.6, 5.9, Lawler 8.8, 8.12, 8.13, Rosenthal 4.1.12, 4.1.13

  • Week 9: (midterm exam 2)

  • Week 10: Lawler 9.1, 9.2, 9.6, additional questions

  • Week 11: Lawler 9.3, additional questions

  • Week 12: Rosenthal 4.3.17, 4.3.18, 4.4.14, 4.4.16, Durrett 2.29