17.1. Strings
17.2. Computational problems
17.3. Computer programs to solve computational problems
17.4. Resources
17.5. Extending the notion of computation
17.6. Classes of problems
17.7. Finding counterexamples
17.8. Conjectures
17.9. Reductions
17.10. Complete and hard problems
17.11. Rice's theorem
17.12. Tools from complexity