| Abstract: |
| We present some recent results about existence and, in some cases,
multiplicity of solutions to boundary value problems associated
with the equation
$$u`` + a(t)g(u) = 0,$$
where $g: I \to {\mathbb R}^+_{0}$ is a (positive) function
defined on an open interval $I$ and $a:[0,T]\to {\mathbb R}$ is a
sign-changing weight. We show some applications to the search of
positive radially symmetric solutions for elliptic equations and
to equations with singularities. |
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