Undecidable Problems: Undecidable problems are computational problems for which no algorithm can determine, in a finite amount of time, whether a given input has a specific property or satisfies a particular condition.
Decision Problems: Decision problems are computational problems that require determining whether an input meets certain criteria by providing either "yes" or "no" as an answer.
Halting Problem: The halting problem is an undecidable problem that asks whether, given an arbitrary program and its input, it will eventually halt (terminate) or run forever.