Prisoner's Dilemma

Prisoner's Dilemma is a good know problem in a field of game theory. Essence of Prisoner's Dilemma lie on the decisions of two prisoners arrested for the same crime, for example robbing some bank. Prisoners are separated in two rooms and each other isn't aware about the decision of the second one.

There are three possible situations, which can happen:
1) Prisoners betrays each other, and each of them stay in jail for 5 years.
2) Both prisoners stays silent, and each of them stay in jail for 2 year.
3) First prisoner betrays the second one, but the second one stays silent. The first prisoner will be free, but the second one stays in jail for 10 years.

The matrix below reflects this situation:

	Prisoner 2 Stays Silent	Prisoner 2 Betrays
Prisoner 1 Stays Silent	2 years for each	10 years for Prisioner 1 0 years for Prisioner 2
Prisoner 1 Betrays	0 years for Prisioner 1 10 years for Prisioner 2	5 yearch for each

If the first prisoner betrays the second one, and the second one stays silent, the first prisoner will be free, but the second prisoner will be arrested for 10 years. This is the best situation for the first prisoner, but the worst for the second prisoner.

But the second prisoner also wants to spend the shortest time possible in the jail, so he is thinking if the first prisoner betrays him, or stay silent. He knows that there is a possibility that the first prisoner betrays him and he knows that in this case it is better to betray the first prisoner also.

You can try Prisoner's Dilemma online game here

Sources:
http://plato.stanford.edu/entries/prisoner-dilemma/
http://en.wikipedia.org/wiki/Prisoner%27s_dilemma

Wiki software

Introduction: Wiki software refers to collaborative software used in creating websites with content consisting of multiple collaboratively created web pages. First such software, called WikWikiWeb, was created by Ward Cunningham for c2.com [Leaf, Cunningham].

Example: Possibly most famous Wiki project is the Wikipedia ( www.wikipedia.org ), a collaborative encyclopedia created by Jimmy Wales and Larry Sanger [Millard]. Which was originally created as a side-project to an english-language and expert-written online encyclopedia Nupedia, but quickly grew into an independent entity.

Basics: Wikis tend to generally be rather basic compared to other content management systems. Generally they are nothing more than linked hypertext pages with heavy focus on the content instead of the layout and structure. Most major wikis tend to have loose licensing and are often available to be edited freely by anyone, often even the ones available only for signed users are free to register on.


Reference:
[Leuf, Cunningham] "The Wiki Way : quick collaboration on the Web", Addison-Wesley, ©2001

[Millard] "Wikipediots: Who are these devoted, even obsessive contributors to Wikipedia?", Salt Lake city weekly, Wednesday, February 20,2008.
Available on: http://www.cityweekly.net/utah/article-5129-feature-wikipediots-who-are-these-devoted-even-obsessive-contributors-to-wikipedia.html