Lagrangian Averaged Navier-Stokes equations with rough data in Sobolev space

We prove the existence of short time, low regularity solutions to the incompressible, isotropic Lagrangian Averaged Navier-Stokes equations with initial data in Sobolev spaces. In the special case of initial datum in the Sobolev space $H^{3/2,2}(\mathbb{R}^3)$, we obtain a global solution, improving on previous results, which required data in $H^{3,2}(\mathbb{R}^3)$.