# Turing Machines--A Primer

DevFeed: [Turing Machines--A Primer](<https://devfeed.tech/articles/turing-machines-a-primer-40218.md>)

Original publisher: [Read original article](<https://www.jeremykun.com/2011/07/04/turing-machines-a-primer/>)

Published: 2011-07-04T16:35:44Z

Content type: tutorial

Language: en

Sources: [Jeremy Kun](<https://devfeed.tech/sources/jeremy-kun.md>)

Topics: [Automaton](<https://devfeed.tech/topics/automaton.md>), [function](<https://devfeed.tech/topics/function.md>)

Tags: [acceptance](<https://devfeed.tech/tags/acceptance.md>), [computability-theory](<https://devfeed.tech/tags/computability-theory.md>), [computers](<https://devfeed.tech/tags/computers.md>), [concepts](<https://devfeed.tech/tags/concepts.md>), [decidability](<https://devfeed.tech/tags/decidability.md>), [halting-problem](<https://devfeed.tech/tags/halting-problem.md>), [input](<https://devfeed.tech/tags/input.md>), [machine](<https://devfeed.tech/tags/machine.md>), [mathematics](<https://devfeed.tech/tags/mathematics.md>), [primer](<https://devfeed.tech/tags/primer.md>), [process](<https://devfeed.tech/tags/process.md>), [pushdown-automata](<https://devfeed.tech/tags/pushdown-automata.md>), [state](<https://devfeed.tech/tags/state.md>), [symbols](<https://devfeed.tech/tags/symbols.md>), [turing-machines](<https://devfeed.tech/tags/turing-machines.md>)

## AI overview

This tutorial introduces Turing machines as a model of computation. It defines their states, tape symbols, input symbols, initial state, accepting and rejecting states, and transition function, then explains how the tape, read-write head, state transitions, and halting behavior work.

## Source excerpt

We assume the reader is familiar with the concepts of determinism and finite automata, or has read the corresponding primer on this blog. The Mother of All Computers Last time we saw some models for computation, and saw in turn how limited they were. Now, we open Pandrora's hard drive: Definition: A Turing machine is a tuple $ (S, \Gamma, \Sigma, s_0, F, \tau)$, where $ S$ is a set of states, $ \Gamma$ is a set of tape symbols, including a special blank symbol $ b$, $ \Sigma \subset \Gamma$ is a set of input symbols, not including $ b$, $ s_0$ is the initial state, $ A \subset S$ is a set of accepting states, $ R \subset S$ is a set of rejecting states, $ \tau: S - (A \cup R) \times \Gamma \to S \times \Gamma \times \left \{ L, R \right \}$ is a partial function called the transition function, where $ L, R$ correspond to "left shift" and "right shift," respectively.