Формули MS Word MathType
Версія від 14:12, 25 грудня 2009, створена WikiSysop (обговорення • внесок)
[math]\operatorname{erfc}(x) = \frac{2}{\sqrt{\pi}} \int_x^{\infty} e^{-t^2}\,dt = \frac{e^{-x^2}}{x\sqrt{\pi}}\sum_{n=0}^\infty (-1)^n \frac{(2n)!}{n!(2x)^{2n}}[/math]
<wikitex> Let $Q$ be any finite set, and $\mathcal B=2^Q$ be the collection of the subsets of $Q$. Let $f:\mathcal B\rightarrow \mathbb R$ be a function assigning real numbers to the subsets of $Q$ and suppose $f$ satisfies the following conditions:
- (i) $f(A)\ge 0$ for all $A\subseteq Q$, $f(\emptyset)=0$,
- (ii) $f$ is monotone, i.e. if $A\subseteq B\subseteq Q$ then $f(A)\le f(B)$,
- (iii) $f$ is submodular, i.e. if $A$ and $B$ are different subsets of $Q$ then
$$ \eqno{(2)}
f(A)+f(B)\ge f(A\cap B) + f(A\cup B).
$$ </wikitex>