Bravyi, E.; Lomtatidze, A.; Půža, B. A note on the theorem on differential inequalities. (English) Zbl 1009.34057 Georgian Math. J. 7, No. 4, 627-631 (2000). The authors consider the Cauchy problem \[ u''(t) = l(u)(t)+q(t), \quad u(a)=c, \] where \(l \) is a linear nonpositive operator. The aim of this note is to derive a necessary condition on \(l \) to be a Volterra operator. Reviewer: E.V.Shchetinina (Berlin) Cited in 3 Documents MSC: 34K06 Linear functional-differential equations 34K12 Growth, boundedness, comparison of solutions to functional-differential equations Keywords:Cauchy problem; linear nonpositive operator PDF BibTeX XML Cite \textit{E. Bravyi} et al., Georgian Math. J. 7, No. 4, 627--631 (2000; Zbl 1009.34057)