### ECS 120 - Winter 98 - List of Lecture Topics

Lecture Topic
Week 0 Lect 1 - R 1/8 Introduction. Three problems of differing hardness. Example DFAs. Strings, languages, classes
Week 1 Lect 2 - T 1/13 Practice with DFA design. Formal definitions of DFAs. Proofs which use induction and pigeonholing
Lect 3 - R 1/15 Closure properties of DFA-acceptable languages (including product construction). NFAs and their definition
Week 2 Lect 4 - T 1/20 Closure properties of NFA-acceptable languages. NFAs accept exactly the DFA-acceptable languages
Lect 5 - R 1/22 Quiz 1. Regular languages and regular expressions. Regular languages are NFA-acceptable
Week 3 Lect 6 - T 1/27 NFA-acceptable-languages are regular. Decision procedures involving regular languages
Lect 7 - R 1/29 Showing languages are not regular with the pumping lemma and closure properties
Week 4 Lect 8 - T 2/3 CFGs. Parse trees. Ambiguity. Closure properties of CLFs. Regular languages are CF. PDAs
Lect 9 - R 2/5 Quiz 2. PDAs. CNF. PDAs. The pumping lemma for CFLs
Week 5 Lect 10 - T 2/10 CFL closure properties. Decision procedures for CFLs. An efficient algorithm for CFL membership.
Lect 11 - R 2/12 Midterm
Week 6 Lect 12 - T 2/17 Definition of TMs and the languages they accept. Some TM variants. The Church-Turing thesis.
Lect 13 - R 2/19 NTMs, unrestricted grammars. Pros & cons of Church-Turing thesis. rec, r.e., co-r.e. sets and their properties
Week 7 Lect 14 - R 2/24 Guessing where languages live: r.e., co-r.e., decidable, neither. Diagnolization. Undecidability of Atm.
Lect 15 - R 2/26 Turing-computable functions and many-one reductions. Properties of reductions. Practice doing reductions
Week 8 Lect 16 - T 3/3 "Practical" undecidable problems: Virus Detection, Starvation Detection. Does a CFG generate all strings?
Lect 17 - R 3/5 Quiz 3. The classes P and NP. The languages NFAEQ, SAT, CLIQUE, COMPOSITES.
Week 9 Lect 18 - T 3/10 SAT, 3SAT, CLIQUE, NFAEQ, G3C. Reductions. Defn of NP-Completeness. SAT<3SAT, 3SAT
Lect 19 - R 3/12 The Cook-Levin Theorem
Week 10 Lect 20 - R 3/17 NP-Completeness of VERTEX COVER and SUBSET SUM. Dealing with NP-hard problems
T 3/24 Final, 7-9 pm, 147 Olson