Randomized Algorithms, F2006.Q3 (F2005)

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Advanced course at the Department of Computer Science, University of Aarhus in the 3rd quarter, Spring 2006.

Usually each two-hour class will start with a lecture and end with a problem session related to the lectures of the previous week.

Literature

Course examination

The course is evaluated by a grade from the 13-scale based on a project and a multiple choice test.

Links

Course Plan (preliminary; revised February 17, 2006)

Feb. 1 Lecture R1 Introduction to randomized algorithms
Randomization on inputs versus algorithms.
Analysis by linearity of expectation and indicator variables.
Las Vegas and Monte Carlo algorithms.
MR 1-1.2

Feb. 3 Lecture R2 Introduction to randomized algorithms (cont.)
Another example of a Las Vegas algorithm and analysis by linearity of expectation.
Proof of existence by the probabilistic method.
A Las Vegas algorithm that beats any deterministic strategy.
The complexity classes RP, BPP.
MR 1.3, 1.5, 2.1
Problems for R1,R2:
MR 1.1, 1.2, 1.4, 1.8
Feb. 8 Lecture R3 Randomized algorithms: Proving lower bounds
von Neumann's minimax principle
Yao's techniques for proving lower bounds
Average case time usage for best deterministic algorithm relative to a known worst case input distribution equals expected time usage of best randomized algorithm on worst case input
MR 2.2

Feb. 10 Lecture R4 Derandomization
Trading randomness for nonuniformity.
Markov's and Chebyshev' inequalities.
Trading time for random bits.
MR 2.3, 3.2, 3.4
Problems for R3,R4:
MR 2.3, 2.7, 2.12
Feb. 15 Lecture R5 Chernoff bounds and randomized rounding
Chernoff Bound: The sum of independent indicator variables is distributed closely around the expectation.
Randomised rounding: Good approximate solutions to hard combinatorial problems.
MR 4.1, 4.3

Feb. 17 Lecture R6 Chernoff bounds (cont.)
Application to analysis of a routing algorithm.
MR 4.2
Problems for R5,R6:
MR 4.12, 4.13, 4.9
Feb. 22 Lecture R7 Algebraic techniques in randomization
Fingerprinting for result checking.
Schwarz-Zippel theorem.
Application to perfect matching.
MR 7-7.3

Feb. 24 Lecture R8 Algebraic techniques (cont.)
Distributed equality test.
(On-line) pattern matching.
MR 7.4-7.6
Problems for R7,R8:
MR 7.2, 7.8, 7.10, 7.12
Mar. 1 Lecture R9 Dictionaries
Universal hashing and dynamic dictionaries.
2-level hashing and static dictionaries.
MR 8.4-8.5

Mar. 3 Lecture R10 Dictionaries (cont.)
Random Treaps
MR 8.2

Mar. 8 Lecture R11 Competitive analysis of on-line algorithms
Competitiveness: Comparison of on-line solution to best off-line solution.
Paging algorithms: deterministic and randomised solutions.
MR 13-13.3

Mar. 10 Lecture R12 Competitive analysis of on-line algorithms
Paging algorithms: Lower bounds on competitiveness using Yao's technique.
MR 13.3
Problems for R11,R12:
MR 13.6, 13.10, 13.12
Mar. 15 Lecture R13 Primality test (if time permits)
Randomised primality test.
Generation of random primes.
MR 14.6
Problems for R13:
MR 14.12
1,2
Mar. 17 Last session
Multiple Choice Test.
Course evaluation.



Last modified: Wed Mar 8 21:18:12 2006.
Gudmund S. Frandsen
gudmund@daimi.au.dk