definiendum | F∈CDF |
inclusion | F:R→R … right-continuous function, monotonically increasing |
postulate | lim |
postulate | \lim_{x\to\ +\infty} F(x)=1 |
P=F'
Let S:({\mathbb D}\to {\mathbb R}_{\ge 0})\to{\mathbb R}_{\ge 0} be linear.
If f with \infty>Sf>0, then \bar{f}:=\frac{1}{Sf}\cdot f has S\bar{f}=\frac{Sf}{Sf}=1.
So we can use such S to normalize functions.
For {\mathbb D}={\mathbb N} the general case is Sf:=\sum_{n=0}^\infty (L_nf)(n), where (L_n) is a suitable sequence of linear operations (e.g. differential operators). For L_n={\mathrm{id}} we get the standard sum (see below).
For {\mathbb D}\subseteq{\mathbb R}^m we have integrals.
Let a:{\mathbb N}\to{\mathbb R}_{\ge 0} be a sequence, then
\bar{a}:{\mathbb N}\to[0,1]
\bar{a}(n):=\frac{1}{\sum_{k=0}^\infty a(k)}\cdot a(n)
has
\sum_{n=0}^\infty \bar{a}(n)=1
The “monomial bump” on [-d,d], which goes against the constant probability \frac{1}{2d} for large n:
P_{n,d}(x):=\frac{1}{2d}\left(1+\frac{1}{2n}\right)\cdot\left(1-\left(\frac{x}{d}\right)^{2n}\right)
\int_{-d}^dP_{n,d}(x)\,{\mathrm d}x=1
Die Funktion hängt mit dem sog. Epanechnikov-Kern zusammen.
Wikipedia: Cumulative distribution function