Rooftop photovoltaic power station Rooftop photovoltaic power station A rooftop photovoltaic power station, or rooftop PV system, is a photovoltaic system that has its electricity-generating solar panels mounted on the rooftop of a residential or commercial building or structure. The various components of such a system include photovoltaic modules, mounting systems, cables, solar inverters and other electrical accessories. Rooftop mounted systems are small compared to ground-mounted photovoltaic power stations with capacities in the megawatt range. Rooftop PV systems on residential buildings typically feature a capacity of about 5 to 20 kilowatts (kW), while those mounted on commercial buildings often reach 100 kilowatts or more.
Injective module number of results are known, . Let "S" and "R" be rings, and "P" be a left-"R", right-"S" bimodule that is flat as a left-"R" module. For any injective right "S"-module "M", the set of module homomorphisms Hom( "P", "M" ) is an injective right "R"-module. For instance, if "R" is a subring of "S" such that "S" is a flat "R"-module, then every injective "S"-module is an injective "R"-module. In particular, if "R" is an integral domain and "S" its field of fractions, then every vector space over "S" is an injective "R"-module. Similarly, every injective "R"["x"]-module is an