Uniqueness of Minimal Realizations up to Similarity applied Input-Output Irrelevance of Hidden Modes in the Kalman Decomposition applied Momentum Map Conservation Theorem applied Stone-von Neumann Theorem applied Horn-SAT admits a polynomial-time decision algorithm applied State-Space Realization Transfer Function Formula applied Subdifferential Formula for the Support Function of a Compact Convex Set applied Moreau-Rockafellar Subdifferential Sum Rule applied