Splitting the Fučík Spectrum and the Number of Solutions to a Quasilinear ODE

Abstract

For $\varnothing$ an increasing homeomorphism from $\mathbb{R}$ onto $\mathbb{R}$ and $f\epsilon C\left(\mathbb{R}\right)$, we consider the problem \[ \left(\varnothing\left(u'\right)\right)'+f\left(u\right)=0,\qquad t\epsilon\left(0,L\right),\qquad u\left(0\right)=0=u\left(L\right). \] The aim is to study multiplicity of solutions by means of some generalized Pseudo Fu$\check{\textrm{c}}$ik spectrum (at infinity, or at zero). New insights that lead to a very precise counting of solutions are obtained by splitting these spectra into two parts, called Positive Pseudo Fu$\check{\textrm{c}}$ik Spectrum (PPFS) and Negative Pseudo Fu$\check{\textrm{c}}$ik spectrum (NPFS) (at infinity, or at zero, respectively), in this form tue can discuss separately the two cases u' (0) > 0 and u' (0) < 0.