The most important sequences spaces in analysis are the ℓ"p" spaces, consisting of the "p"-power summable sequences, with the "p"-norm. These are special cases of L"p" spaces for the counting measure on the set of natural numbers. Other important classes of sequences like convergent sequences or null sequences form sequence spaces, respectively denoted "c" and "c"0, with the sup norm. Any sequence space can also be equipped with the topology of pointwise convergence, under which it becomes a special kind of Fréchet space called an FK-space.