A mathematical model of computing. The versatility of modern computers and their applications to the study of complex and dynamic systems, such as financial markets, cellular growth, and communication networks, raise questions about the ultimate power of computers. For example, what are the limitations, if any, on the tasks that we can ask computers to perform? Can we use computers to carry out any computational task we want? To answer such questions, we generally make use of abstract mathematical models. One of the most important mathematical abstract models that has been widely used to simulate objects and processes such as computer and digital circuits is automata theory.