PageHeader : Funkcialaj Ekvacioj, 1 (195S), 77?132 Title : Non-linear Ordinary Differential Equations Title : with Periodic Coefficients AuthorInfo : By Yasutaka SIBUYA AuthorInfo : (Ochanomizu University) section : Introduction section : CONTENTS. section : CHAPTER I. LINEAR ORDINARY DIFFERENTIAL EQUATIONS WITH BOUNDED COEFFICIENTS CONTAINING A FINITE NUMBER OF PARAMETERS subsection : 1. Differential equations with bounded coefficients subsubsection : 1. 1. Formal reduction. subsection : 1. 2. Convergence of the series $Q(t, a)$ . subsection : 2. Differential Equations with periodic coefficients subsubsection : 2. 1. Formal reduction. subsubsection : 2. 2. Convergence of the series $Q(t, a)$ . subsubsection : 2. 3. Equations of Mathieu. subsubsection : 2. 4. Remarks. section : CHAPTER II. FORMAL REDUCTION OF NON-LINEAR ORDbNARY DIFFERENTIAL EQUATIONS WITH BOUNDED COEFFICIENTS subsection : 3. Formal reduction subsubsection : 3. 1. The case of bounded coefficients. subsubsection : 3. 2. The case of almost periodic coefficients. subsubsection : 3. 3. The case of periodic coefficients. subsection : 4. Classical results subsubsection : 4. 1. Lemmas. Now we shall prove the following two lemmas: subsubsection : 4. 2. Classical results. section : CHAPTER III. BOUNDED SOLUTIONS OF NON-LINEAR ORDINARY DIFFERENTIAL EQUATIONS WITH ALMOST PERIODIC COEFFICIENTS subsection : 5. Remarks on the solutions of the differential equations (3. 1. 5) subsubsection : 5. 1. The case of bounded coefficient. subsubsection : 5. 2. The case of almost periodic coefficients. subsection : 6. Bounded solutions of the system (3. 1. 1) with almost periodic $\mathrm{c}\dot{\mathrm{o}}\mathrm{e}\mathrm{f}\mathrm{f}\mathrm{i}\mathrm{c}\mathrm{i}\mathrm{e}\mathrm{n}\mathrm{t}\mathrm{s}$ subsubsection : 6. 1. Solutions bounded in [ $0,$ $+\infty)$ . subsubsection : 6. 2. Almost periodic solution. subsubsection : 6. 3. Remarks on the general solutions. subsubsection : 6. 4. The case $\lambda_{i}$ are purely imaginary. section : CHAPTER IV. NON-LINEAR ORDINARY DIFFERENTIAL EQUATION WITH BOUNDED COEFFICIENTS CONTAINING A FINITE NUMBER OF PARAMETERS subsection : 7. Preliminary remarks subsubsection : 7. 1. Reduction of problem. subsection : 8. Formal reduction subsubsection : 8. 1. The case of bounded coefficients. subsubsection : 8. 2. Remarks on the case of almost periodic coefficients. subsection : 9. Convergence of formal solutions subsubsection : 9. 1. Preliminary remarks. subsubsection : 9. 2. Convergence of the formal solution (9. 1. 21). section : CHAPTER V. PF.RIODIC SOLUTIONS subsection : 10. Formal calculation subsubsection : 10. 1. Auxiliary equations. subsubsection : 10. 2. Convergence of the formal series. subsection : 11. Conditions of periodicity subsubsection : 11. 1. Main theorem. subsubsection : 11. 2. Differential equations containing parameters. subsection : 12. Application of formal reductions subsubsection : 12. 1. Formal solutions. subsubsection : 12. 2. Criterion for convergence. subsubsection : 12. 3. Applications of the criterion. subsubsection : 12. 4. Remarks on existence of periodic solutions. subsubsection : 12. 5. The case of algebraic functions. subsection : 13. Autonomous systems subsubsection : 13. 1. Preliminary remarks. subsubsection : 13. 2. The case $\omega_{0}=0$ . subsubsection : 13. 3. The case $\omega_{0}\neq 0$ . subsubsection : 13. 4. Convergence of the formal solution. section : References subsection : Supplement to References