Editing Recursively enumerable language (section)

==Example==
The set of [[Halting Problem|halting Turing machines]] is recursively enumerable but not recursive. Indeed, one can run the Turing machine and accept if the machine halts, hence it is recursively enumerable. On the other hand, the problem is undecidable.

Some other recursively enumerable languages that are not recursive include:

* [[Post correspondence problem]] 
* [[Mortality (computability theory)]]
* [[Entscheidungsproblem]]