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.
Module (mathematics) to zero by "f". The isomorphism theorems familiar from groups and vector spaces are also valid for "R"-modules. The left "R"-modules, together with their module homomorphisms, form a category, written as "R"-Mod (see category of modules for more.) This is an abelian category. Finitely generated. An "R"-module "M" is finitely generated if there exist finitely many elements "x", ..., "x" in "M" such that every element of "M" is a linear combination of those elements with coefficients from the ring "R". Cyclic. A module is called a cyclic module if it is generated by one element. Free. A free "R"-module