Discrete mathematics is a mathematical discipline that studies the structure and relationship of discrete quantities and an important branch of modern mathematics. The meaning of discreteness refers to different connecting elements. The structure based on discreteness and the relationship between them are mainly studied, and its objects are generally finite or countable elements. Discrete mathematics is widely used in various disciplines, especially in the field of computer science and technology. At the same time, discrete mathematics is also a necessary prerequisite for many professional courses of computer specialty, such as programming language, data structure, operating system, compilation technology, artificial intelligence, database, algorithm design and analysis, theoretical computer science foundation and so on.

Second, the application:

1. set theory: sets and their operations, binary relations and functions, natural numbers and natural number set, cardinality of sets.

2. Combinatorial mathematics: combinatorial existence theorem, basic counting formula, combinatorial counting method and combinatorial counting theorem.

3. Combinatorial mathematics: combinatorial existence theorem, basic counting formula, combinatorial counting method and combinatorial counting theorem.

4. Mathematical logic: propositional logic, first-order predicate calculus and resolution principle.