Can anyone tell me if there's a way to relate the eigendecomposition of the result of a summation of matrices with the eigendecomposition of those matrices? More specifically: If I have a matrix $K = \sum\limits_{m=1}^M a_m K_m$, $a_m \in R$.
How can I relate its eigendecomposition, $K = V \Lambda T^T$, with the eigendecomposition of the matrices in the summation, i.e. $K_m = V_m \Lambda_m V_m^T$?