The incompressible Euler equations under octahedral symmetry: Singularity formation in a fundamental domain.

We consider the 3D incompressible Euler equations in vorticity form in the following fundamental domain for the octahedral symmetry group: { (x 1 , x 2 , x 3) : 0 < x 3 < x 2 < x 1 }. In this domain, we prove local well-posedness for C α vorticities not necessarily vanishing on the boundary with any 0 < α < 1 , and establish finite-time singularity formation within the same class for smooth and compactly supported initial data. The solutions can be extended to all of R 3 via a sequence of reflections, and therefore we obtain finite-time singularity formation for the 3D Euler equations in R 3 with bounded and piecewise smooth vorticities. [ABSTRACT FROM AUTHOR]