## Tags » Math.AP

#### Conserved quantities for the surface quasi-geostrophic equation

As in the previous post, all computations here are at the formal level only.

Expository

#### Noether's theorem, and the conservation laws for the Euler equations

Throughout this post, we will work only at the formal level of analysis, ignoring issues of convergence of integrals, justifying differentiation under the integral sign, and so forth. 2,057 more words

Expository

#### Conserved quantities for the Euler equations

The Euler equations for incompressible inviscid fluids may be written as

where is the velocity field, and is the pressure field. To avoid technicalities we will assume that both fields are smooth, and that is bounded. 1,792 more words

Expository

#### Finite time blowup for an averaged three-dimensional Navier-Stokes equation

I’ve just uploaded to the arXiv the paper “Finite time blowup for an averaged three-dimensional Navier-Stokes equation“, submitted to J. Amer. Math. Soc.. The main purpose of this paper is to formalise the “supercriticality barrier” for the global regularity problem for the Navier-Stokes equation, which roughly speaking asserts that it is not possible to establish global regularity by any “abstract” approach which only uses upper bound function space estimates on the nonlinear part of the equation, combined with the energy identity. 1,957 more words

Paper