Este blog tem como objectivo levar a cabo o que indica o título - um passeio pela Matemática. Dar a conhecer a sua História, as suas leis, as suas personagens e curiosidades, enfim divulgar esta Ciência que, como disse Victor Duruy, é a chave de ouro com que podemos abrir todas as ciências.

quarta-feira, 23 de janeiro de 2013

O Paradoxo da Amizade

«It’s a mathematical fact. Your friends are probably more popular than you are.

Don’t believe it? Consider this: the average Facebook user has 245 friends, but the average friend on Facebook has 359 friends, according to a 2011 Pew survey.

That’s right. The average person on Facebook has fewer friends than their friends do.

But how can that be? It definitely seems weird, and that’s why this phenomenon is known as “friendship paradox,” described in a 1991 paper by Scott L. Feld amusingly titled “Why Your Friends Have More Friends Than You Do.”

It turns out the paradox is not so mysterious, however, when you take a closer look at the math. Below I will give an example of the friendship paradox and then go through the math of why it happens.»

Ler na íntegra aqui.

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