“…For simplicity, we suppose the kinematic viscosity 𝜈 to be equal to 1. In the case that Ω is bounded, we add Navier boundary conditions u • n = 0, [((∇u) + (∇u) T )n] 𝜏 + 𝛾u = 𝟎 on 𝜕Ω × (0, T), (4) where 𝛾 > 0 denotes the friction coefficient between the fluid and the fixed wall and n is the outer normal vector on 𝜕Ω, or Navier-type boundary conditions u • n = 0, 𝝎 × n = 𝟎 on 𝜕Ω × (0, T), (5) where 𝝎 = ∇ × u, or Dirichlet boundary conditions u = 𝟎 on 𝜕Ω × (0, T). (6) In this paper, we study the conditional regularity of the weak solutions to the Navier-Stokes equations.…”