“…If, further, the vortex viscosity χ = 0, the velocity u does not depend on the micro-rotation field ω, and the first equation reduces to the classical Navier-Stokes equation which has been greatly analyzed, see, for example, the classical books by Ladyzhenskaya [13], Lions [15] or Lemarié-Rieusset [14]. If we ignore the micro-rotation of particles, it reduces to the viscous incompressible magnetohydrodynamic equations, which has also been studied extensively [1][2][3]9,20]. It is worthy to note that He and Xin [9], Zhou [25,26] proved the regularity criteria of weak solutions to the magneto-hydrodynamic equations, which only need the velocity u or its gradient ∇u or the vorticity ∇ × u or p and b or ∇p and b to satisfy some conditions.…”