Decidability
- Abstraction Operator
- Church's Theorem
- Complete Axiomatic Theory
- Creative Set
- Decidable
- Decision Problem
- Existence
- Existence Problem
- Existence Proof
- Gödel's Completeness Theorem
- Gödel's First Incompleteness Theorem
- Gödel Number
- Gödel's Second Incompleteness Theorem
- Goodstein Sequence
- Goodstein's Theorem
- Hidden Zero
- Incompleteness
- Iteration Theorem
- Kleene's Recursion Theorem
- Kleene's s-m-n Theorem
- Kreisel Conjecture
- Lambda Calculus
- Many-One Complete
- mu-Operator
- One-One Complete
- Paris-Harrington Theorem
- Presburger Arithmetic
- Productive Set
- Quantifier Elimination
- Recursion Theorem
- Recursive Set
- Recursively Enumerable Set
- Recursively Undecidable
- Rice's Theorem
- Richardson's Theorem
- Satisfiability Problem
- Tarski's Theorem
- Undecidable