In this work, we have investigated the validity of GSL of thermodynamics in a
universe (open, closed and flat) governed by Horˇava-Lifshitz
gravity. If the universe contains barotropic fluid the corresponding solutions
have been obtained. The validity of GSL have been examined by two approaches:
(i) robust approach and (ii) effective approach. In robust approach, we have
considered the universe contains only matter fluid and the effect of the
gravitational sector of HL gravity was incorporated through the modified black
hole entropy on the horizon. Effective approach is that all extra information
of HL gravity into an effective dark energy fluid and so we consider the
universe contains matter fluid plus this effective fluid. This approach is
essentially same as the Einstein's gravity theory. The general prescription for
validity of GSL have been discussed. Graphically we have shown that the GSL may
be satisfied for open, closed and flat universe on the different horizons with
different conditions.Comment: 7 latex pages, 7 figure