We consider a nonlinear Robin problem driven by the sum of $p$-Laplacian and $q$-Laplacian (i.e. $(p,q)$-equation). In reaction there are competing effects singular term parametric perturbation $\lambda f(z,x)$, which is Carath\'eodory $(p-1)$-superlinear at $x\in\mathbb{R},$ without satisfying Ambrosetti-Rabinowitz condition. Using variational tools, together with truncation comparison techniq...

Abstract: Let G = (VG, EG) be a simple connected graph. The eccentric distance sum of G is defined as ξ(G) = ∑ v∈VG εG(v)DG(v), where εG(v) is the eccentricity of the vertex v and DG(v) = ∑ u∈VG dG(u, v) is the sum of all distances from the vertex v. In this paper the tree among n-vertex trees with domination number γ having the minimal eccentric distance sum is determined and the tree among n-...