Task: Text Categorization
Input (English): One of these entities that represents the location of vertices on a graph is the ""adjacency"" type. One used to identify resemblances between two data points is a similarity type. A collection of second-order partial derivatives of a function may be collected in a Hessian one of these entities. First-order derivatives are collected in the Jacobian one. If one of these entities is invertible, it is row-equivalent to an identity variety, and its determinant is nonzero. Multiplication of these entities is notably not commutative. For 10 points, name this rectangular array of numbers.
Output (English): Science