When the sieve works

When the Sieve Works

We are interested in classifying those sets of primes P such that when we sieve out the integers up to x by the primes in P we are left with roughly the expected number of unsieved integers. In particular, we obtain the first general results for sieving an interval of length x with primes including some in ( √ x, x], using methods motivated by additive combinatorics.

When expert advice works, and when it does not

0th experts and users of expertise fail to grasp the role. of expertise in decision making. Of course, expert advice is essential in complex human activities, but those who follow that advice also sometimes regret it. Under what conditions does expert advice and action tend to produce satisfactory outcomes? Recent studies of technological controversies and governmental regulatory procedures rev...

Experiments with Kemeny ranking: What works when?

This paper performs a comparison of several methods for Kemeny rank aggregation (104 algorithms and combinations thereof in total) originating in social choice theory, machine learning, and theoretical computer science, with the goal of establishing the best trade-offs between search time and performance. We find that, for this theoretically NP-hard task, in practice the problems span three reg...

When and Why Ruppert's Algorithm Works

An “adaptive” variant of Ruppert’s Algorithm for producing quality triangular planar meshes is introduced. The algorithm terminates for arbitrary Planar Straight Line Graph (PSLG) input. The algorithm outputs a Delaunay mesh where no triangle has minimum angle smaller than 26.45◦ except “across” from small angles of the input. No angle of the output mesh is smaller than arctan [(sin θ∗)/(2 − co...

When Child Welfare Works: A Working Paper