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We investigate the dynamical horizon area law formalism with a torus topology in its cross section. A special solution of Einstein equations of the general Vaidya form with a flat torus topology on the cross section of its dynamical horizon is put forward. The solution, having a dynamical horizon has a non-vanishing matter flux inside the horizon and therefor increase in the area of its horizon cross section. We have shown that with vanishing matter flux inside the horizon, this horizon becomes the isolated horizon. Finally, we find that the dynamical horizon area law matched to the stationary case.
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