Fractional Navier–Stokes regularity criterion involving the positive part of the intermediate eigenvalue of the strain matrix

This paper proves the regularity criterion for the solutions of the 3D fractional Navier–Stokes equations in terms of the positive part of the intermediate eigenvalue of the strain matrix, which can be regarded as an improvement and extension of the results obtained by Miller [Arch. Ration. Mech. Anal. 235, 99–1139 (2020)] and by Wu [Evol. Equations Control Theory 10, 511–518 (2021)].