Theory of computation

In computability theory, the Church–Turing thesis (also known as Computability Thesis, the Turing–Church thesis, the Church–Turing conjecture, Church's thesis, Church's conjecture, and Turing's thesis) is a hypothesis about the nature of computable functions.

Computable functions are the basic objects of study in computability theory.

Gödel's incompleteness theorems are two theorems of mathematical logic that demonstrate the inherent limitations of every formal axiomatic system containing basic arithmetic.

In computability theory, primitive recursive functions are a class of functions that are defined using primitive recursion and composition as central operations and are a strict subset of the total µ-recursive functions (µ-recursive functions are also called partial recursive).

A randomized algorithm is an algorithm that employs a degree of randomness as part of its logic.

Recursion occurs when a thing is defined in terms of itself or of its type.

A Turing machine is an abstract machine that manipulates symbols on a strip of tape according to a table of rules; to be more exact, it is a mathematical model of computation that defines such a device.

Quantum information science is an area of study based on the idea that information science depends on quantum effects in physics.

In computability theory and computational complexity theory, a decision problem is a question in some formal system with a yes-or-no answer, depending on the values of some input parameters.

A flowchart is a type of diagram that uses an algorithm, workflow or process, showing the steps as boxes of various kinds, and their order by connecting them with arrows.

In computability theory, the halting problem is the problem of determining, from a description of an arbitrary computer program and an input, whether the program will finish running or continue to run forever.

A Nassi–Shneiderman diagram (NSD) in computer programming is a graphical design representation for structured programming.

Recursion in computer science is a method where the solution to a problem depends on solutions to smaller instances of the same problem (as opposed to iteration).

Self-reference occurs in natural or formal languages when a sentence, idea or formula refers to itself.

The Post correspondence problem is an undecidable decision problem that was introduced by Emil Post in 1946.

The Busy Beaver Game consists of designing a halting, binary-alphabet Turing Machine which writes the most 1s on the tape, using only a limited set of states.