Irena Rachunkova, Department of Math.,
Palacky University, 779 00 OLOMOUC, Tomkova 40, Czech Republic,
e-mail: rachunko@risc.upol.cz;
Milan Tvrdy, Mathematical Institute, Acad. Sci.of the
Czech Republic, 115 67 PRAHA 1, Zitna 25, Czech Republic, e-mail:
tvrdy@math.cas.cz,
http://www.math.cas.cz/~tvrdy/;
Summary:
In this paper, using the lower/upper functions argument, we establish new existence results for the nonlinear impulsive periodic boundary value problem
where f fulfils the Caratheodory conditions on $[0,T]\times R^2$ and $J_i, M_i$ are continuous on R. The main goal of the paper is that the lower/upper functions $\sigma_1 / \sigma_2$ associated with the problem are not well-ordered, i.e. $\sigma_1\not\le\sigma_2$ on [0,T].
Keywords: Second order nonlinear ordinary differential equation with impulses, periodic solutions, lower and upper functions, Leray-Schauder topological degree, a priori estimates.
Mathematics Subject Classification 2000: 34B37, 34B15, 34C25 .
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