That assumption refers to hash tables, and a conjecture based on work from the 1980s regarding the optimal way to store and query the data in them. The student, formerly of Rutgers University in ...

A young computer scientist and two colleagues show that searches within data structures called hash tables can be much faster than previously deemed possible.

Making fast hash tables in programming, which don't cause collision trouble, is one of computing's holy grails. Facebook thinks it's created a good one.