@article{10902/37975,
year = {2023},
url = {https://hdl.handle.net/10902/37975},
abstract = {We deal with a planar differential system of the form {u'=h(t,v),v'=Ya(t)g(u), where h is T-periodic in the first variable and strictly increasing in the second variable, Y>0, a is a sign-changing T-periodic weight function and g is superlinear. Based on the coincidence degree theory, in dependence of Y, we prove the existence of T-periodic solutions (u,v) such that u(t)>0 for all tER. Our results generalize and unify previous contributions about Butler's problem on positive periodic solutions for second-order differential equations (involving linear or O-Laplacian-type differential operators).},
publisher = {Elsevier},
publisher = {Journal of Differential Equations, 2023, 363, 546-581},
title = {Periodic solutions to superlinear indefinite planar systems: A topological degree approach},
author = {Feltrin, Guglielmo and Sampedro Pascual, Juan Carlos and Zanolin, Fabio},
}