Turing, Alan M.
On Computable Numbers, with an Application to the Entscheidungsproblem
Proceedings of the London Mathematical Society
1936
2
230–265
42
http://www.cs.helsinki.fi/u/gionis/cc05/OnComputableNumbers.pdf
Turing's famous demonstration of the formal limits on computation
based on a proof that the \em halting problem is undecidable.
computability, tcs, logic