A SISO linear system is said to have symmetric state space (SSS), whenever: A=A^{T}, \, b=c . This type of systems appear in many important applications, such as in the analysis of RC circuits and in inverse problems involving 3D Maxwell's equations. For SSS systems with distinct poles, the following convergence result has been proven: "IRKA is a locally convergent fixed point iteration to a local minimizer of the H_{2} optimization problem."
