Earlier this summer Dr Bearman reported, in the American Journal of Sociology, an examination of high-school students' sexual activity and romantic relationships.

ECONOMIST: What maths tells us about us

First I read comic books, then adventure books, a few romantic novels, the Spanish literature she was studying at school, as well as the Catalan, Manelic and the wolf, and all that.

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When he plotted these as a graph, he found that it usually took many links (the record was 37, in a 500-pupil school) to get from one individual to another via an intervening chain of romantic entanglements if, indeed, it were possible to make a connection at all.

ECONOMIST: What maths tells us about us

Mr. Boarman, whose first job out of high school was working at a printing company in downtown Washington, said he has a "romantic" attachment to the Printing Office name, but noted that much of the work is electronic nowadays.

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