Example image of eyePlorer eyePlorer map for 'Formal language': Set (mathematics) String (computer science) Symbol (formal) Alphabet (computer science) Formal grammar Formation rule Well-formed formula Computer science Linguistics Semantics Data format Programming language Compiler Compiler-compiler Lex (software) Lexical analysis Yacc Formal semantics of programming languages Foundations of mathematics Logic Formal system Logical consequence Proof calculus Alfred Tarski First-order logic T-schema Alphabet ASCII Character encoding Tuple Kleene star Concatenation Subset Natural language Context-free language Regular language Natural number Syntax Alphanumeric Context-free grammar Turing machine Algorithm Automata theory Decision problem Finite-state machine Regular expression Computability Computational complexity theory Chomsky hierarchy Parsing