11. For other computational and complexity subjects, see list of computability and complexity topics. 12. In computability theory in computer science, it is common to consider formal languages. 13. Other formal attempts to characterize computability have subsequently strengthened this belief ( see below ). 14. It developed into a study of abstract computability , which became known as recursion theory. 15. Another semantics uses Japaridze s computability logic. 16. His own research was in computability theory. 17. Indeed, the Turing Machine was not even the first published formal model of computability . 18. Many mathematicians and computational theorists who study recursion theory will refer to it as computability theory. 19. He is a past president of the ACM Special Interest Group on Algorithms and Computability Theory. 20. Therefore the question of computability of proofs is not separated from the question of their existence.
