# Nonlinear stability of explicit self-similar solutions for the timelike extremal hypersurfaces in R^{1+3}

## TL;DR

This paper investigates the nonlinear stability of explicit lightlike self-similar solutions representing spheres for timelike extremal hypersurfaces in Minkowski space, revealing their role as attractors and addressing spectral analysis challenges.

## Contribution

It identifies explicit self-similar solutions, analyzes their linear instability, and proves their nonlinear stability within a specific region, overcoming spectral analysis difficulties.

## Key findings

- Self-similar solutions are nonlinearly stable attractors.
- Linear mode instability is established for these solutions.
- Spectral analysis was advanced by constructing a Newton's polygon.

## Abstract

This paper is devoted to the study of the singularity phenomenon of timelike extremal hypersurfaces in Minkowski spacetime $\mathbb{R}^{1+3}$. We find that there are two explicit lightlike self-similar solutions to a graph representation of timelike extremal hypersurfaces in Minkowski spacetime $\mathbb{R}^{1+3}$, the geometry of them are two spheres. The linear mode unstable of those lightlike self-similar solutions for the radially symmetric membranes equation is given. After that, we show those self-similar solutions of the radially symmetric membranes equation are nonlinearly stable inside a strictly proper subset of the backward lightcone. This means that the dynamical behavior of those two spheres is as attractors. Meanwhile, we overcome the double roots case (the theorem of Poincar\'{e} can't be used) in solving the difference equation by construction of a Newton's polygon when we carry out the analysis of spectrum for the linear operator.