Title: Theory (and Some Practice) of Randomized Algorithms for Matrices and Data Speaker: Michael W. Mahoney (Stanford University) Abstract: Matrix problems are ubiquitous in many large-scale data applications, and in recent years randomization has proved to be a valuable resource for the design of better algorithms for many of these problems. Depending on the situation, better might mean faster in worst-case theory, faster in high-quality numerical implementation, e.g., in RAM or in parallel and distributed environments, or more useful for downstream domain scientists. The talk will describe the theory underlying randomized algorithms for matrix problems such as least-squares regression and low-rank matrix approximation. Although the use of randomization is sometimes a relatively-straightforward application of Johnson-Lindenstrauss ideas, Euclidean spaces are much more structured objects than general metric spaces, and thus the best---both in theory and in numerical analysis and data analysis practice---randomized matrix algorithms take this into account. An emphasis will be placed on highlighting a few key concepts that are responsible for the improvements in worst case theory and also for the usefulness of these algorithms in large-scale numerical and data applications