Lighting a particular area, and falls within a given solid angle. The SI unit for luminance is candela per square metre (cd/m). The CGS unit of luminance is the stilb, which is equal to one candela per square centimetre or 10 kcd/m. The amount of useful light emitted from a source or the luminous flux is measured in lumen (lm). The SI unit of illuminance and luminous emittance, being the luminous power per area, is measured in Lux. It is used in photometry as a measure of the intensity, as perceived by the human eye, of light that hits or passes
Radon measure letting the "y"-axis have measure 0 and letting the point (1/"n","m"/"n") have measure 1/"n". This measure is inner regular and locally finite, but is not outer regular as any open set containing the "y"-axis has measure infinity. In particular the "y"-axis has "m"-measure 0 but "M"-measure infinity. A topological space is called a Radon space if every finite Borel measure is a Radon measure, and strongly Radon if every locally finite Borel measure is a Radon measure. Any Suslin space is strongly Radon, and moreover every Radon measure is moderated. On a locally compact Hausdorff space, Radon measures correspond to