Relaxation for degenerate nonlinear functionals in the onedimensional case
Valeria Chiadò Piat, Virginia De Cicco, Anderson Melchor Hernandez
TL;DR
The paper studies the relaxation of a degenerate nonlinear functional in one dimension, where F(u) is the weighted p-energy with weight w. A key idea is to construct an auxiliary weight hat w_p dependent on p and w to define an appropriate domain and to enable L^p convergence with respect to (hat w_p)^{p-1}. A weighted Poincaré inequality with a double weight is proved, linking the weighted gradient energy to the weighted L^p norm and enabling density results for AC functions. Under the finitely degenerate weight assumption, the authors derive an explicit relaxation: Fbar(u) equals the weighted energy on the degeneracy set for u in Dom_w and is infinite otherwise; AC(Ω̄) density in the associated Sobolev space is established, while the non-finitely degenerate case remains open.
Abstract
In this study, we approach the analysis of a degenerate nonlinear functional in one dimension, accommodating a degenerate weight $w$. Our investigation focuses on establishing an explicit relaxation formula for a functional exhibiting $p$-growth for $1< p<+\infty$. We adopt the approach developed in [6], where some assumptions like doubling or Muckenhoupt conditions are dropped. Our main tools consist of proving the validity of a weighted Poincaré inequality involving an auxiliary weight.
