“…𝑡 ≥ 0 0 ≤ 𝜆(𝑡) ⊥ 𝑤 (𝑡) = 𝐶𝑥 (𝑡) + 𝐷𝜆(𝑡) + 𝐹 (𝑡) ≥ 0, for all 𝑡 ≥ 0 with 𝑥 (𝑡) ∈ ℝ 𝑛 , 𝜆(𝑡) ∈ ℝ 𝑚 , 𝐴, 𝐵, 𝐶, 𝐷 constant matrices of appropriate dimensions, 𝑃 ∈ ℝ 𝑛×𝑛 has rank 𝑝 < 𝑛. Dissipativity is a fundamental property in Systems and Control [25,87,88]. The material in this article relies on a result in [28,32,51] on a special Weierstrass form for passive descriptor variable systems [25,Section 3.1.7] which possess a minimal state-space realization [28,Theorem 3.1]. The passivity of the quintuple (𝑃, 𝐴, 𝐵, 𝐶, 𝐷) means the passivity of the operator 𝜆 ↦ → 𝑤, see Appendix d. Assuming that 𝐸 (𝑡) = 0 and 𝐹 (𝑡) = 0, passivity and minimality, this special form writes as (see [51] [32, Equation ( 16)] [28, Proposition A.3]):…”