Neutral Functional Differential Equations with Applications to Compartmental Systems

The paper’s Theorem 5.7 (existence of almost periodic solutions and asymptotic almost periodicity; plus infinitely many almost periodic solutions for closed systems) is proved via the D-order, mass functional M, uniform stability (F6), and a 1-cover property for omega-limit sets, all under (C1)–(C5) and the hypothesis that a bounded solution exists; the argument is coherent and correctly cited in the text. By contrast, the model’s Phase-2 proof hinges on an unsubstantiated fiberwise exponential contraction derived from a Halanay-type inequality. The claimed inequality α>β is not entailed by (C5) as used, indices are mismatched, and the proof omits the paper’s crucial hypothesis “existence of a bounded solution.” Consequently, the model’s proof is incorrect/incomplete, even though some conclusions coincide with the paper’s.