This is a preview. Log in through your library . Abstract Let A be an n × n matrix whose elements are independent random variables with standard normal distributions. As n → ∞, the expected number of ...

We propose a new approach for estimating high-dimensional, positive-definite covariance matrices. Our method extends the generalized thresholding operator by adding an explicit eigenvalue constraint.

The Nature Index 2024 Research Leaders — previously known as Annual Tables — reveal the leading institutions and countries/territories in the natural and health sciences, according to their output in ...