What is Decision problem?
[[Image:Decision Problem.svg|thumb|200px|A ''decision problem'' has only two possible outputs, ''yes'' or ''no'' (or alternately 1 or 0) on any input.]] In [[computability theory]] and [[computational complexity theory]], a '''decision problem''' is a question in some [[formal system]] with a yes-or-no answer. The answer is dependent on the values of the input parameters. Decision problems typically appear in mathematical questions of [[Decidability theory|decidability]], that is, the question of the existence of an [[effective method]] to determine the existence of some object or its membership in a [[set]]. Some of the most important problems in mathematics are [[undecidable]]. [[Category:Mathematical problems]] [[Category:Decision theory]]