Computable functions Sequential machine theory 5 Machine theory 4 Logic, Symbolic and mathematical 2 Model theory 2 Proof theory 2 Recursive functions 2 Algorithms 1 Computational complexity 1 Computer programming 1 Data structures (Computer Science) 1 Electronic data processing 1 Functional programming languages 1 Mathematics 1 Nonclassical mathematical logic 1 Recursion theory 1 Set Theory 1