Disperser


A disperser is a one-sided extractor. Where an extractor requires that every event gets the same probability under the uniform distribution and the extracted distribution, only the latter is required for a disperser. So for a disperser, an event we have:
Definition : A -disperser is a function
such that for every distribution on with the support of the distribution is of size at least.

Graph theory

An -disperser is a bipartite graph with N vertices on the left side, each with degree D, and M vertices on the right side, such that every subset of K vertices on the left side is connected to more than M vertices on the right.
An extractor is a related type of graph that guarantees an even stronger property; every -extractor is also an -disperser.

Other meanings

A disperser is a high-speed mixing device used to disperse or dissolve pigments and other solids into a liquid.