13.07.2015 Views

Immunology as a Metaphor for Computational ... - Napier University

Immunology as a Metaphor for Computational ... - Napier University

Immunology as a Metaphor for Computational ... - Napier University

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

E £ f 2 ¥£Appendix A. Coincidences in permutations and schedules 194place!Thus, no matter how long the permutation, you expect just one item to be in itsWhat is the variance of f ? Consider E £ f 2 ¥§¥ :n∑n∑E f j £ ¥ E f k £ ¥1 k 1 jn∑∑E f j f k ¥£1 k 1 j£ ¥ ¥1n jn j knn∑ E f j 2 2 ∑ E f j f k1nBut f j is just 0 or 1, so f j 2 f j , so E f j 2 E f £ ¥ j 1< n. Also, E f £ ¥ j f k is the ¥probability that a permutation h<strong>as</strong> both j and k in place, £ namely, 2¥ !< n 1< n! n n£. There<strong>for</strong>e,£ 1¥E £ f 2 ¥ 1 2 n £ n 1¥§< 2¥a 1< n £ n 1¥ 2and the variance of f is there<strong>for</strong>e E £ f 2 ¥ E £ f ¥ 2 2 1 1.

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!