grandes-ecoles 2017 QI.B.2

grandes-ecoles · France · centrale-maths2__psi Matrices Matrix Norm, Convergence, and Inequality
Verify the following property: $\forall A \in \mathcal { M } _ { n } ( \mathbb { C } ) , \forall Y \in \mathbb { C } ^ { n } \quad \| A Y \| _ { \infty } \leqslant n \| A \| _ { 0 } \cdot \| Y \| _ { \infty }$
Verify the following property: $\forall A \in \mathcal { M } _ { n } ( \mathbb { C } ) , \forall Y \in \mathbb { C } ^ { n } \quad \| A Y \| _ { \infty } \leqslant n \| A \| _ { 0 } \cdot \| Y \| _ { \infty }$