J. J. Nieto

Document Type


Source Publication Title

Technical Report 181


Recently [7,8,10] an attempt is made successfully to combine the two basic techniques namely, Lyapunov-Schmidt method and the method of upper and lower solutions, to investigate the existence of periodic solutions of differential equations. When we wish to extend such results for systems of differential equations there are two possibilities to follow. One is to generalize the method of upper and lower solutions using a suitable cone, and the other is to utilize the concept of tyapunov-like functions and the theory of differential inequalities. In the paper, we shall discuss the existence of problems at resonance for first and second order differential systems by the second approach developing necessary theory of differential inequalities for problems at resonance.


Mathematics | Physical Sciences and Mathematics

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Mathematics Commons



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