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Abstract

With the help of a generalized Raychaudhuri equation non-expanding null surfaces are studied in an arbitrary dimensional case. The definition and basic properties of non-expanding and isolated horizons known in the literature in the four- and three-dimensional cases are generalized. A local description of the horizon's geometry is provided. The zeroth law of black-hole thermodynamics is derived. The constraints have a similar structure to that of the four-dimensional spacetime case. The geometry of a vacuum isolated horizon is determined by the induced metric and the rotation 1-form potential, local generalizations of the area and the angular momentum typically used in the stationary black-hole solutions case.