Recent research has explored various aspects of complexity theory, including connections between graph theory and matrix spaces, the computation of determinants, and optimization problems.

Indeed, to date, no practical algorithm for estimating the permanent of a matrix has been devised. It is an open question whether such an algorithm exists. Another open question is whether there is a ...

A simple matrix formula is given for the observed information matrix when the EM algorithm is applied to categorical data with missing values. The formula requires only the design matrices, a matrix ...

Current leading approaches to this problem are based on estimating the full covariance matrix between the proxy time series and instrumental time series over a "calibration" interval and then using ...