Vertex Operator Algebras (VOAs) are mathematical structures that arise in the study of two-dimensional conformal field theory and string theory. They provide a framework for understanding the algebraic properties of vertex operators, which encode the interactions of particles in a quantum field. VOAs consist of a vector space equipped with a vertex operator, a grading by integers, and a set of axioms that govern the algebraic operations. They play a crucial role in various areas of mathematics, including representation theory, modular forms, and string theory, allowing for the exploration of symmetries and the classification of different algebraic objects.