Existence and uniqueness of the solution to a fourth order nonlinear vector periodic boundary value problem is proved by using the estimates for derivatives of the Green function for the corresponding homogenous scalar problem
@article{107489, author = {\v Ludov\'\i t Pinda}, title = {On a fourth order periodic boundary value problem}, journal = {Archivum Mathematicum}, volume = {030}, year = {1994}, pages = {1-8}, zbl = {0808.34020}, mrnumber = {1282107}, language = {en}, url = {http://dml.mathdoc.fr/item/107489} }
Pinda, Ľudovít. On a fourth order periodic boundary value problem. Archivum Mathematicum, Tome 030 (1994) pp. 1-8. http://gdmltest.u-ga.fr/item/107489/
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