Issue on new trends in nonlinear PDEs:
Dedicated to Professor Vicentiu D. Radulescu, on the occasion of his 65th birthday

Preface
Chao Ji and Binlin Zhang

On a Hamiltonian elliptic system with concave and convex nonlinearities
Oscar Agudelo, Bernhard Ruf and Carlos Veléz

Concentration phenomenon for a fractional Schrödinger equation with discontinuous nonlinearity
Vincenzo Ambrosio

Positive solutions for nonlinear singular problems with sign-changing nonlinearities
Yunru Bai, Nikolaos S. Papageorgiou and Shengda Zeng

Minimax principles for mixed variational inequalities driven by uniformly monotone operators
Michał Bełdziński, Marek Galewski and Filip Pietrusiak

High energy positive solutions for a coupled Kirchhoff system
Li Cai, Qiang Lin and Fubao Zhang

Parametric anisotropic double phase free boundary problems with nonlocal terms and convection: Existence, stability and asymptotic behavior
Jinxia Cen, Leszek Gasiński, Calogero Vetro and Shengda Zeng

On isolated singular solutions of semilinear Helmholtz equation
Huyuan Chen and Feng Zhou

Existence and multiplicity of sign-changing solutions for gauged nonlinear Schrödinger systems in $\mathbb{R}^2$
Chunping Duan and Jianjun Zhang

Asymptotic symmetry and monotonicity of solutions for weighted fractional parabolic equations
Jing Feng, Yunyun Hu and Ye Li

Existence and blow-up behavior of positive solutions to integral equations on bounded domains
Qianqiao Guo and Ruiyu Qi

Qualitative behavior of solutions for a class of coupled nonlinear Klein-Gordon equations with strongly damping terms
Siyan Guo, Jie Liu and Yanbing Yang

The qualitative behavior for one-dimensional sixth-order Boussinesq equation with logarithmic nonlinearity
Zhuang Han, Runzhang Xu and Yanbing Yang

A Vázquez-type strong minimum/maximum principle for partial trace operators
Bukayaw Kindu, Ahmed Mohammed and Birilew Tsegaw

On multi-bump solutions for the Choquard-Kirchhoff equations in $\mathbb{R}^N$
Shuaishuai Liang, Mingzhe Sun, Shaoyun Shi and Sihua Liang

Normalized solutions to fractional Schrödinger equation with potentials
Mei-Qi Liu and Wenming Zou

On the higher order mean curvatures of spacelike hypersurfaces in pp-wave spacetimes
Giovanni Molica Bisci, José H. H. de Lacerda, Henrique F. de Lima and Marco A. L. Velásquez

Blowup phenomena for a fourth order wave equation at high initial energy level
Tiantian Pang, Lanlan Qin and Xingchang Wang

The Brézis–Nirenberg equation for the $(m, p)$ Laplacian in the whole space
Patrizia Pucci and Linlin Wang

Existence of positive solution for a class of quasilinear Schrödinger equations with critical Choquard nonlinearity
Sushmita Rawat and Sreenadh Konijeti

On the Fučik spectrum for the $p,q$-Laplacian
Abdolrahman Razani and Giovany M. Figueiredo

Nodal solutions for critical Robin double phase problems with variable exponent
Francesca Vetro and Patrick Winkert

Fractional weighted $p$-Kirchhoff equations with general nonlinearity
Mingqi Xiang and Chaoqun Song

Normalized ground states for the lower critical fractional Choquard equation with a focusing local perturbation
Shubin Yu, Chunlei Tang and Ziheng Zhang

On the Kirchhoff equation with prescribed mass and general nonlinearities
Xiaoyu Zeng, Jianjun Zhang, Yimin Zhang and Xuexiu Zhong

Ground state sign-changing solutions for the Chern-Simons-Schrödinger equation with zero mass potential
Ning Zhang, Xianhua Tang and Heilong Mi

Existence and asymptotic behaviour of the least energy solutions for a quasilinear Dirac-Poisson system
Fan Zhou, Zifei Shen and Minbo Yang