When implementing a nonlinear constraint in quantum field theory by means of Lagrange multiplier, $\ensuremath{\lambda}(x)$, it is often the case that dynamics induce quadratic and even higher-order terms which then does not enforce anymore. This illustrated unimodular gravity, where metric tensor has to be ($g(x)\ensuremath{\equiv}\mathrm{det}\text{ }{g}_{\ensuremath{\mu}\ensuremath{\nu}}(x)=\...

In this paper we consider   multivariate Lagrange mean-value interpolation problem, where interpolation parameters are integrals over spheres. We have   concentric spheres. Indeed, we consider the problem in three variables when it is not correct.