Independent set: let s be a vertex subset of graph g. If any two vertices in S are not adjacent, then S is an independent set of vertices of G. ..
Coverage: If a set A is divided into several non-empty subsets called blocks, so that each element in A belongs to at least one block, then the set composed of all these blocks is called a cover. ..
For example, let A={a, b, c}, B={{a, b}, {b, c}}, C={{a}, {a, b}, {a, c}}, then both b and c are different covers of a.
Matching: Let G be a graph and M be included in E(G). If the edge in M is a bar and any two edges are not adjacent, M and G are said to match.
2.
Set is a basic concept that cannot be defined accurately. In layman's terms, putting something together to form a whole is called a collection.
Function: Let X and Y be any two sets, and F is the relationship from X to Y. If each x∈X has a unique Y, let < X, Y > ∈ F, and call the relationship F a function;
Binary relation: Let A and B be any two sets, and the subset R of A × B becomes a binary relation from A to B. When A=B, R is called a binary relation on A. ..
Function is a special binary relation, and binary relation is a set of ordered pairs.
3.
Set theory is a mathematical theory to study sets, including the most basic mathematical concepts such as sets, elements and subordinate relations.
Graph theory is a branch of mathematics. It takes graphics as the research object. A graph in graph theory is a graph composed of several given points and lines connecting the two points. This kind of figure is usually used to describe a certain relationship between some things, with points representing things and lines connecting two points indicating that there is such a relationship between two corresponding things.
Discrete mathematics is a branch of modern mathematics, and it is a course to cultivate students' meticulous thinking, rigorous reasoning and comprehensive inductive analysis ability.
Discrete mathematics includes set theory and graph theory.