On the monotonicity of the time-map
The authors deal with the equation \(\Delta u(x)+f(u(x))=0,\) \(| x| <R\) together with the boundary conditions \(\alpha u(x)-\beta du(x)/dn=0,\) \(| x| =R\), and investigate the monotonicity of the time map \(p\mapsto T(p)\), \(p=u(0)\) which plays an important role in the behaviour of radical solutions and in symmetry breaking.
scientific article; zbMATH DE number 4101612