| distribution assigning to any function f(x), continuous for , the value f(0)|
Note 1 to entry: The Dirac function can be considered as the limit of a function, equal to zero outside a small interval containing the origin, and the integral of which remains equal to unity when this interval tends to zero. See Figure 2, where instead of a triangle any other shape with area 1 is possible, too.
Note 2 to entry: The Dirac function is the derivative of the unit step function considered as a distribution.
Note 3 to entry: The Dirac function can be defined for any value x0 of the variable x. The usual notation is:
Figure 1 – Distribution de Dirac
Figure 1 – Dirac function