ECS 120: Theory of Computation
ECS 120: Theory of Computation (Fall 2011, UC Davis). Instructor: Professor Dan Gusfield. This is a rigorous undergraduate course on the Theory of Computation, using the classic text "Introduction to the Theory of Computation" by Michael Sipser. The course covers machine models and languages defined by Finite State Machines, Context-Free Languages, and Turing Machines. There are four major theorems (and their uses) that we will study during this course, providing complete proofs: the pumping Lemma for regular languages, used to show that there are languages that are not regular; the existence of a Universal Turing Machine; undecidability of the Halting problem; and Cook's theorem that NP-complete problems exist. In addition to these major results, and other results, a central goal of the course is to increase student's skill level in understanding and writing rigorous mathematical proofs.
| Lecture 05 - Regular Expressions, Regular Languages and Non-Regular Languages |
Completion of equivalence of regular languages and regular expressions. Introduction to the proof that there are languages that are not regular; first an ad hoc proof using the essence of the pumping lemma, but without formally stating it.
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