Coreset

In computational geometry and approximation algorithms, a coreset is a small, possibly weighted subset of an input point set that approximately preserves the value of a specified optimization problem. Solving the problem on the coreset instead of the full data set yields a solution provably close to optimal, and coresets are widely used in geometric optimization, cluster analysis, data streams, and machine learning to reduce computational cost while retaining theoretical guarantees. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/