Measure Theory and Stochastic Processes II
2013-2014
Duisenberg School of Finance

Aim

To make students familiar with the mathematical fundamentals of stochastic processes and stochastic integrals.

Contents

Construction of Brownian motion from symmetric walk by the central limit theorem, martingale property and quadratic variation; construction of the Itô integral, fundamental properties (Itô isometry); Itô rule (in one and more dimensions), stochastic product rule, Lévy's characterization of Brownian motion; absolutely continuous change of measure, Girsanov's theorem, martingale representation theorem; stochastic differential equations, diffusions and partial differential equations, Feynman-Kaç formula, stopping times;
If times permits also: Poisson and compound Poisson process, decomposition of compound Poisson processes, quadratic variation, Itô formula for processes with jumps, change of measure for jump-diffusions, extension of Girsanov's theorem.

Prerequisites

Basic concepts of probability and measure theory, as given in the course by Laurens de Haan.

Literature

The course is mainly based on Steve Shreve, Stochastic Calculus for Finance II, Continuous-Time Models, Springer (2004).

Examination

Weekly a set of homework assignments and a final written exam at the end. You are required to work in pairs (and a pair means two people only!) for the homework. Deadlines are always a week after the assignment has been made known. The written exam is on October 21, 2013 (09:30-12:30).

People

Lectures by Peter Spreij, tutorials by Marius Zoican.

Schedule

Location

Duisenberg school of finance, Gustav Mahlerlaan 117, 1082 MS Amsterdam (travel directions).

Programme (WEEKLY ADJUSTED!)
(last modified: )

1a
Class: Random walk, Central limit theorem, Brownian motion, martingale, quadratic variation; from Shreve, most (but not all!) of sections 3.1-3.4.
1b
Class: Integral of simple functions, construction of stochastic integral w.r.t. Brownian motion, properties (isometry), general integrands; from Shreve, most of sections 4.1 - 4.3
TA session: Exercises 3,4, 3.6, 4.2 and 4.4 if time permits
Homework: Exercises 3.1, 3.2, 4.1; read Section 3.2.7, a motivation for the use of Brownian motion in finance (but you have to know the Binomial model for stock prices...).
2a
Class: Itô integral continued, $\int_0^TW(t)\,\mathrm{d}W(t)$, Itô-formula for Brownian motion and Itô processes, deterministic integrands; from Shreve, theory of Section 4.4.6
2b
Class: multivariate Brownian motion, product rule, Levy's characterization, Change of measure, Girsanov's theorem; from Shreve, Sections 4.6.1, parts of 4.6.2 and 4.6.3, 5.2.1
TA session: Exercises 4.5, 4.6, 4.8, 5.1
Homework: Understand the examples in Section 4.4, pay attention to the parts of Section 4.6 that I skipped, and make exercises 4.7, 4.14, 5.2
3a
Class: Girsanov and risk neutral pricing in finance, martingale representation theorem, start with Poisson processes; from Shreve, Sections 5.2.2-5.2.4, 5.3, 11.2
3b
Class: Compound Poisson process, integrals w.r.t. jump processes; from Shreve, Section 11.3, 11.4
TA session: Exercises 5.5, 5.8, 5.11 (if there is enough time), Example 11.4.6 in detail. Extra: Given a compound Poisson process (notation as in Shreve), find a left continuous process $Y$ such that $Q(t)=\int_0^t Y(s)\,\mathrm{d}N(s)$. Show (argue) that $\mathbb{E}\int_0^t Y(s)\,\mathrm{d}s=\beta t$ and relate this to Theorem 11.3.1.
Homework: Read Section 5.4.1 and (if you like) more on derivative pricing in Section 5.4 to get an idea why the change of measure is useful and necessary in finance, have a look at the Summary (Section 5.7) and the Notes (Section 5.8) as well. Make Exercise 8.3(a,b,c) from the lecture notes of another course in which you have to find the process $\Gamma$ of Theorem 5.3.1 for the martingales in the exercise (do this for $t < T$ only). Don't get confused by the notation $X\cdot W$. It means stochastic integral, not a product (this notation is not uncommon, by the way, see also Williams for a discrete time version). Further: Exercises 11.1 (first (ii), than (i)), 11.2, 11.3




Links

Korteweg-de Vries Institute for Mathematics
Master Stochastics and Financial Mathematics