Geometric properties and non-blowup of 3-D incompressible Euler flow
  By exploring a local geometric property of the vorticity field along a vortex filament, we establish a sharp relationship between the geometric properties of the vorticity field and the maximum vortex stretching. This new understanding leads to an improved result of the global existence of the 3-D Euler equation under mild assumptions that are consistent with the observations from recent numerical computations. 
Jian Deng, Thomas Y. Hou, Xinwei Yu