This article develops some general theory for testing the rank of a matrix. Applications include tests of interaction in two-factor experiments that are more powerful than the usual F test for certain ...

Four researchers have recently come out with a model that upends the conventional wisdom in their field. They have used intensive computational data to suggest that for decades, if not longer, ...

Mathematicians love a good puzzle. Even something as abstract as multiplying matrices (two-dimensional tables of numbers) can feel like a game when you try to find the most efficient way to do it.