References [CLR] Thomas H. Cormen, Charles E. Leiserson and Ronald L. Rivest, Introduction to Algorithms, The MIT Press, 1990. [Sip] Michael Sipser, Introduction to the Theory of Computation, PWS Publishing Company, 1997. [PAP] Christos H. Papadimitriou, Computational Complexity, [MR] Rajeev Motwani, Prabhakar Raghavan, Randomized Algorithms Addison-Wesley Publishing Company, 1995. [V] Vijay V. Vazirani, Approximation Algorithms. Springer. 1 1 2 1.03.04 Oded 4.03.04 Amnon 8.03.04 Oded 2 11.03.04 Amnon 3 15.04.04 Oded 3 18.03.04 Amnon 22.03.04 Oded 25.03.04 Amnon 4 4 5 5 6 29.03.04 Oded 15.04.04 Amnon 19.04.04 Oded Complexity of functions. [CLR 2-4], [Sip 7.1] Turing Machines (example – palindromes). [PAP 2.1-2.3], Multiple tape T.M. vs. Single tape ones. [PAP 2.3],[Sip 3.2] (doesn’t include time analysis). Time and Space complexity. [PAP 7.1] The class P. [PAP 2.6] Multiple tape – cont. s-t-connectivity –in SPACE(log2n) – an explicit machine. [PAP 7.3], [Sip 8.1] Composition of space bounded machines. s-t-connectivity –in SPACE(log2n) – the more general framework. [PAP 7.3] Diagonalization and universal TM for Halt [PAP 3.1-2] and for complexity class separation – The Time and space hierarchies. [PAP 7.2] Non-deterministic TM – two possible definitions. NTIME. Co-classes. [PAP 2.7,7.1] Diagonalization and universal TM for Halt and for complexity class separation. [PAP 7.2], [Sip 9.1] Circuits [PAP 11.4] Reductions, [PAP 8.1] STCONN is NL-complete [PAP 7.3,16.1], CVAL is P-Complete [PAP 8.2] . CVAL is P-Complete [PAP 8.2] NP. All guesses can be made at beginning. NP as a game between an all powerful prover and a polynomial time verifier. CSAT is NP-Complete. SAT, 3SAT are NP-Complete. [PAP 8.2,9.2] 2SAT is in P, in fact in co-NL. [PAP 9.2] 2-SAT is in co-NL. [PAP 9.2] 3-Col is NPC assuming 3-NAE is NPC. [PAP 9.3] Clique, IS, VC, SetCover are NP-complete. [PAP 9.2,9.3] Approximation algorithms [V 2.1] Approximating VC with a factor of 2 [PAP 13.1] Approximating Set-Cover with a factor ln(n). Self reducibility of 3-SAT: reducing the search to the decision problem by a polynomial Turing/Cook reduction. [PAP 10.3] 6 7 7 22.04.04 Amnon Tirgul (taught over several weeks) D-HP, D-HC, U-HC, TSP and TSP with triangle inequality. [PAP 9.3] 2-approximation and 1.5 approximation for TSP with triangle inequality. [V 3.2] 3-NAE < MAX-CUT 0.5 approximation for max-cut. 29.04.04 Amnon 3.05.04 Oded TQBF-k is Sigma_k complete. [PAP 17.2] NL=coNL [PAP 7.3]. Separating AvP from EXP Separating P from Time(2n) Separating AvP from Time(2n) [ans2] Parallel computation, [PAP 15.1] . sorting in parallel. NC [PAP 15.3]. NC in DSPACe(polylog(n)) . Perfect Matching in a bipartite graph. Solving by determinants. A randomized algorithm. 4-NAE is NPC, 3-NAE is NPC. PSPACE = NPSPACE revisited. Pratt's Theorem. Probabilistic computation [PAP 11.1,11.2]. Amplification. Chernoof. Schwartz's lemma, Perfect Matching in bipartite graph in RNC. matrix-multiplication-verification. Checking x=y with low communication complexity. [MR 7.4] The min-cut algorithm. [MR 1.1, 10.2] BPP can be solved by polynomial-size circuits. [PAP 11.4] BPP in Sigma_2 . [PAP 17.2] GNISO has an interactive proof! Interactive proofs with public and private coins. A detailed proof of coNP is in IP. Arithmization. Low degree extension. . [PAP 19.2] A short discussion of Multi-prover proofs and the MIP=NEXP result. Oded: A randomized algorithm for pattern matching, IP IN PSPACE. [Oded Goldreich’s lecture notes] [Mathematica file] PCP as an interactive proof system, one round, few bits read from the witness. Encoding the witness so that a single error propagates everywhere. PCP(log(n),1) reduces to sat, and is in NP. An equivalent formulation to the PCP theorem: Gap-Max3sat is NP-hard. Hardness of approximating Max-3SAT. Clique is hard to approximate to within some constant factor. . [VAZ 29.1-3] 8 6.04.04 Amnon 8 10.05.04 Oded 9 13.05.04 Amnon 10 08.05.2003 11 15.05.2003 Oded 12 Padding argument [PAP 20.1] applied to ex2 q6 [ans2] and to Savitch theorem. TQBF is PSPACE-complete. [PAP 19.1] Oracle machines[PAP 14.3] ; PH in terms of oracles, Sigma_k=co-Pi_k. 22.05.2003 13 29.05.2003 Reducing the error with few random bits by a random walk on Exapnders (informal). NP in PCP(O(log n),O(log n)) with 1/n error. Clique is hard to approximate to within some n^a, for some constant a [VAZ 29.6]. Max 3SAT[29] is hard to approximate to within some constant [VAZ 29.4].