INFORMATION THEORY 2005 - 2006

dr. Peter van Emde Boas
 
 
 

EXERCISES  (First and final posting  May 08 2006)

The excercises, unless indicated otherwise, are selected from our textbook
Elements of Information Theory by Thomas M. Corver and Joy A. Thomas.

Answers should be returned by end the end of the course year (say in June 2006), preferably on paper.

Later submission is accepted as well, but don't expect evaluation on short notice in that case.

Electronic submissions causing processing problems will be rejected.

Cooperation between students is permitted under the following conditions:

-- the group shoudn't exceed three people.
-- the cooperation must be clearly indicated on all solutions submitted
-- a group starting to cooperate must persist in this cooperation till the end
   of the course.
-- the group will be graded as a collective; it is the responsibility of the
    people cooperating to prevent abuses.

 
Use of the teacher's support manual which exists for this book (supposed to be unavailable to students) is strictly forbidden.
In case of noticeble similarity between the solutions submitted and this (or other inelegible material) may lead to
disqualification of the results whence no grade will be given for the course.

Chapter 2.   
 

2.1    Flipping a coin until success.

2.2    Are values relevant?

2.3    Characterization of minimal entropy distributions.

2.5    Computation reduces Entropy

2.6    When does conditional entropy vanish?

2.7    How to obtain fair coin flips from a biased coin.

2.9    A discrete source with infinite Entropy.

2.10   Conditionalizing may both increase and decrease shared uinfdormation.

2.14   Impact of replacement when drawing multiple balls from an urn.

2.18   Entropy of the sum of two sources.

2.28   Impact of mixing.

2.32   When does processing not affect conditional Entropy?


Chapter  3


3.2    Another limit

3.3    AEP and source coding

3.6    Two approaches at radom boxes in unbounded dimension


Chapter  4

4.1    Doubly Stochastic Matrices

4.2    Predicting the future versus reconstructing the past

4.4    Some inequalities for stationary processes

4.8    Pairwise independence isn't full independence !

4.11  A random walk on a small chessboard


Chapter  5


5.1    Which Inequalities can you expect to hold?

5.2    Find the unknown alphabet size

5.3    Strict inequality and undecodable messages

5.4    Construction of a Huffman code

5.5    Sensitivity of Huffman coding result for the actual distribution.

5.6    Impossible Huffman outputs.

5.9    Optimal code length exceeding the entropy by almost one

5.14  Yet another Huffman code

5.24   An algorithmic test for unique decodability.


Chapter  7


7.1    Kolmogorov Complexity of a pair of sequences

7.2    Kolmogorov Complexity of the sum of two numbers

7.3    Kolmogorov Complexity of simple pictures z  

7.4    Kolmogorov Complexity of useful programs  

7.10   More Kolmogorov Complexity of Pictures;  NB! I consider the phrasing of the Excercise Ambiguous,
         so you should make explicit how you interprete this question.


Chapter  8


8.1    An instance of misguided assistance

8.2    Analysis of a simple repetition code

8.5    Channel capacity of a symmetric channel

8.6    Channel capacity of pair of channels.