Theoretical computer science is a branch of computer science that focuses on the mathematical and abstract aspects of computation. It explores fundamental concepts such as algorithms, data structures, and computational complexity, which help in understanding how problems can be solved using computers. This field provides the foundation for designing efficient software and hardware systems. Researchers in theoretical computer science study models of computation, such as Turing machines and finite automata, to analyze what can be computed and how efficiently. They also investigate complexity classes like P and NP to categorize problems based on their difficulty. This theoretical framework is essential for advancements in technology and computer applications.