| | Encyclopedia: Distribution (Site not responding. Last check: 2007-10-27) |
 | | If f : R → R is an integrable function, and φ : R → R is a smooth (that is, infinitely differentiable) function with compact support (that is, it is identically zero except on some bounded set), then ∫fφdx is a real number which linearly and continuously depends on φ. |
 | | These distributions are useful if one studies the Fourier transform in generality: all tempered distributions have a Fourier transform, but not all distributions have one. |
 | | Tempered distributions generalize the bounded (or slow-growing) locally integrable functions; all distributions with compact support and all square-integrable functions can be viewed as tempered distributions. |
| www.nationmaster.com /encyclopedia/Distribution (1660 words) |