17642 Computational complexity

Spring 2004, L-T-P: 3-1-0, Credits: 4

Class timings

Schedule:     Wednesday  5:30pm--7:30pm(Lecture)
      Thursday  5:30pm--7:30pm(Lecture/Tutorial)
Venue:     CSE 302
First meeting:     Jan 5, 04

Prerequisites

Tentative syllabus

1. Introduction  

Turing machines, equivalence of reasonable models of computation, non-determinism, algorithms, decision versus optimization problems, reduction between problems.
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2. Time complexity  

The complexity classes P, NP, Co-NP and Exp, completeness for NP, Cook's theorem, some well-known NP-complete problems, classes FP, FNP, TFNP and FNP-Complete, approximation algorithms.
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3. Space complexity  

Classes PSPACE, NSPACE and PSPACE-complete, Savitch's theorem, logarithmic space, classes PolyL, L, NL, Co-NL and NL-complete.
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4. Intractability  

Space and time hierarchy, EXPSPACE-completeness, alternating Turing machines and the polynomial hierarchy, relativization and oracle Turing Machines.
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5. Randomized computation  

Classes RP, ZPP, PP and BPP.
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6. Parallel computation  

Circuit complexity, classes NC and RNC, P-completeness.
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7. Cryptography  

One-way functions, public-key cryptography, interactive protocols.

Textbooks

[ Moret ]   Bernard M E Moret, The Theory of Computation, Addison-Wesley, 1998. [Webpage for the book]
[ Papa ]   Christos H Papadimitriou, Computational complexity, Addison-Wesley, 1994. [Webpage of the author]
[ Sipser ]   Michael Sipser, Introduction to the Theory of Computation, PWS Publishing Company 1997. [Webpage for the book]

Indian editions are available for [ Moret ] and [ Sipser ]. At least a dozen copies of [ Papa ] are available in the Central Library. Students can consult any of the above three books. I think [ Sipser ] is the easiest to follow (in this lot), though it covers a little less than our intended syllabus. [ Papa ] is the de facto standard on this subject, but is very terse and difficult for not-so-serious reading. I found [ Moret ] too verbose and having somewhat non-smooth English.

I will mostly follow [ Sipser ] with occassional detours to [ Papa ].

Examinations


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