Weak inverse

A weak inverse, also known as a pseudoinverse in the context of matrices, is a generalization of the concept of an inverse for non-square or non-invertible matrices. In more formal terms, if \( A \) is a real \( m \times n \) matrix, the weak inverse \( A^+ \) of \( A \) can be defined such that: 1. \( A A^+ A = A \) 2.