In this chapter we review several mathematical topics that form the foundation of probability and mathematical statistics. These include the algebra of sets and functions, general relations with special emphasis on equivalence relations and partial orders, and some basic combinatorial structures such as permuations and combinations.

- Sets
- Functions
- Relations
- Partial Orders
- Equivalence Relations
- Cardinality
- Counting Measure
- Combinatorial Structures
- Measure Theory

- Sets
- Functions
- Relations
- Partial Orders
- Equivalence Relations
- Cardinality
- Counting Measure
- Combinatorial Structures
- Measure Theory
- Answers to selected exercises

Combinatorics is a rich and beautiful mathematical subject in its own right, not just because of its connection to probability.

- Applied Combinatorics, by Fred Roberts
- Applied Combinatorics, by Alan Tucker
- An Introduction to Probability and Its Applications, by William Feller

Later generations will regard set theory as a disease from which one has recovered.

--Henri Poincaré