摘要

Let v(x, t) = v(r)e(r) + v(theta)e(theta) + v(z)e(z) be a solution to the three-dimensional incompressible axially-symmetric Navier-Stokes equations. Denote by b = v(r)e(r) + v(z)e(z) the radial-axial vector field. Under a general scaling invariant condition on b, we prove that the quantity Gamma = rv(theta) is Holder continuous at r = 0, t = 0. As an application, we prove that the ancient weak solutions of axi-symmetric Navier-Stokes equations must be zero (which was raised by Koch, Nadirashvili, Seregin and Sverak (2009) in [15] and Seregin and Sverak (2009) in [26] as a conjecture) under the condition that b is an element of L(infinity)([0, T], BMO(-1)). As another application, we prove that if b is an element of L(infinity)([0, T], BMO(-1)), then v is regular.