Diagonalization argument: Difference between revisions

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A '''diagonalization argument''' is a general format of argument that is used to show the existence of a language that lies outside a certain complexity class or cannot be decided by machines of a certain type. The classic application is to showing the existence of [[undecidable language]]s via the [[halting problem]].
A '''diagonalization argument''' is a general format of argument that is used to show the existence of a language that lies outside a certain complexity class or cannot be decided by machines of a certain type. The classic application is to showing the existence of [[undecidable language]]s via the [[halting problem]].
These arguments are adaptations of the [[Canton diagonalization argument]] that shows that a set (whether finite or infinite) cannot be put in bijection with its power set.

Revision as of 02:03, 28 December 2011

Definition

A diagonalization argument is a general format of argument that is used to show the existence of a language that lies outside a certain complexity class or cannot be decided by machines of a certain type. The classic application is to showing the existence of undecidable languages via the halting problem.

These arguments are adaptations of the Canton diagonalization argument that shows that a set (whether finite or infinite) cannot be put in bijection with its power set.