Given two matrices $A,B \in \mathcal{M}_n (\mathbb{K})$, and let $\rho(A)$, $\rho(B)$ be the absolute values of its biggest eigenvalues, respectively. It's easy to find examples of matrices such that $\rho(A)+ \rho(B) \geq \rho(A+B)$, but can the converse happen?
Are there matrices $A,B \in \mathcal{M}_n (\mathbb{K})$ such that $\rho(A)+ \rho(B) \lt \rho(A+B)$?
$$A=\pmatrix{0&1\\0&0}$$ $$B=\pmatrix{0&0\\1&0}$$ $\rho(A)=\rho(B)=0$, $\rho(A+B)=1$.