Almost periodic upper and lower solutions
نویسندگان
چکیده
The method of upper and lower solutions is a classical tool in the theory of periodic differential equations of the second order. We show that this method does not have a direct extension to almost periodic equations. To do this we construct equations of this type without almost periodic solutions but having two constants as ordered upper and lower solutions. r 2003 Elsevier Science (USA). All rights reserved.
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