Topic summary
Decision procedure
Extracted from the Wikipedia article Decision problem.
A decision procedure for a decision problem is an algorithmic method that answers the yes-no question on all inputs, and a decision problem is called decidable if there is a decision procedure for it. For example, the decision problem "given two numbers x and y, does x evenly divide y?" is decidable since there is a decision procedure called long division that gives the steps for determining whether x evenly divides y and the correct answer, YES or NO, accordingly. Some of the most important problems in mathematics are undecidable, e.g. the halting problem.