Undecidable Problem: 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.
Halting Problem: 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.