Written by the Fiveable Content Team • Last updated August 2025
Verified for the 2026 exam
Verified for the 2026 exam•Written by the Fiveable Content Team • Last updated August 2025
Definition
A decidable problem is a computational problem for which there exists an algorithm that can determine whether a given input has a specific property or satisfies a certain condition.
An undecidable problem is a computational problem for which no algorithm can determine whether a given input has a specific property or satisfies a certain condition.
The halting problem refers to the question of whether an arbitrary program will halt (terminate) or run forever when executed on some input.
Turing Machine: A Turing machine is an abstract mathematical model used to simulate any computer algorithm. It consists of an infinite tape divided into cells, and the machine can read, write, and move along the tape based on its current state.