Extending infinity harmonic functions by rotation
Electronic journal of differential equations, Tome 2015 (2015)
If $u(\mathbf{x}, y)$ is an infinity harmonic function, i.e., a viscosity solution to the equation $-\Delta_\infty u=0$ in $\Omega \subset \mathbb{R}^{m+1}$ then the function $v(\mathbf{x}, \mathbf{z})= u(\mathbf{x}, \|\mathbf{z}\|)$ is infinity harmonic in the set $\{(\mathbf{x}, \mathbf{z}): (\mathbf{x}, \|\mathbf{z}\|)\in \Omega\}$ (provided $u(\mathbf{x},-y)=u(\mathbf{x},y))$.
@article{EJDE_2015__2015__a62,
author = {Gripenberg, Gustaf},
title = {Extending infinity harmonic functions by rotation},
journal = {Electronic journal of differential equations},
year = {2015},
volume = {2015},
zbl = {1320.31015},
language = {en},
url = {http://geodesic.mathdoc.fr/item/EJDE_2015__2015__a62/}
}
Gripenberg, Gustaf. Extending infinity harmonic functions by rotation. Electronic journal of differential equations, Tome 2015 (2015). http://geodesic.mathdoc.fr/item/EJDE_2015__2015__a62/