29
Oct
2012

Too smart

Par Manu ·  Etiquette(s) : In English, Maths, Google, Cryptographie

Some people are just so smart, they can't think like normal people. When the mathematician Zach Harris received an email from Google, he noticed a security vulnerability. Instead of telling Google about it, he…

Harris thought there was no way Google would be so careless, so he concluded it must be a sly recruiting test to see if job applicants would spot the vulnerability.

This reminded me of this passage from Neal Stephenson's Cryptonomicon :

They gave him an intelligence test. The first question on the math part had to do with boats on a river: Port Smith is 100 miles upstream of Port Jones. The river flows at 5 miles per hour. The boat goes through water at 10 miles per hour. How long does it take to go from Port Smith to Port Jones? How long to come back?

Lawrence immediately saw that it was a trick question. You would have to be some kind of idiot to make the facile assumption that the current would add or subtract 5 miles per hour to or from the speed of the boat. Clearly, 5 miles per hour was nothing more than the average speed. The current would be faster in the middle of the river and slower at the banks. More complicated variations could be expected at bends in the river. Basically it was a question of hydrodynamics, which could be tackled using certain well-known systems of differential equations. Lawrence dove into the problem, rapidly (or so he thought) covering both sides of ten sheets of paper with calculations. Along the way, he realized that one of his assumptions, in combination with the simplified Navier Stokes equations, had led him into an exploration of a particularly interesting family of partial differential equations. Before he knew it, he had proved a new theorem. If that didn't prove his intelligence, what would?

Neal Stephenson – Cryptonomicon

Manu