# Oracle machine

In complexity theory and computability theory, an oracle machine is an abstract machine used to study decision problems. It can be visualized as a Turing machine with a black box, called an oracle, which is able to solve certain decision problems in a single operation. The problem can be of any complexity class. Even undecidable problems, such as the halting problem, can be used.

## Words

This table shows the example usage of word lists for keywords extraction from the text above.

Word | Word Frequency | Number of Articles | Relevance |
---|---|---|---|

oracle | 4 | 1744 | 0.403 |

machine | 5 | 17275 | 0.361 |

complexity | 3 | 3523 | 0.276 |

computability | 2 | 150 | 0.263 |

turing | 2 | 609 | 0.228 |