3 problems

Let $A$ be a matrix, let $u$ and $v$ be vectors, and consider the rank-one perturbed linear system $(A+uv^T)x=b$. A system is numerically nonsingular when it is sufficiently nonsin…

Let $A$ be a nonsingular matrix and let $u$ and $v$ be vectors such that $A+uv^T$ is nonsingular. Let $\epsilon_M$ denote the unit roundoff, and let…

Let $A$ be a matrix, let $u$ and $v$ be vectors, and let $\tilde A=A+uv^T$. Let $\epsilon_M$ denote the unit roundoff, and let $\kappa(\cdot)$ denote the matrix condition number. S…