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\documentclass[]{slides}
\begin{document}
delta-distribution
$$
f_\delta(x;\mu,\sigma) =
\frac{C_\delta(\delta^2\sigma^2)^{1+\delta^2/2}}
{[(x-\mu)^2+\delta^2\sigma^2]^{3/2+\delta^2/2}}
$$
$$
C_\delta = \frac{\Gamma(3/2+\delta^2/2)}{\Gamma(1/2)/\Gamma(1+\delta^2/2)}
$$
$$\frac12 < C_\delta < \frac1{\sqrt\pi}\simeq 0.5642$$
$$
\int dx\ f_\delta(x;\mu,\sigma) = 1,\quad \forall \delta
$$
$$
\int dx\ (x-\mu)^2f_\delta(x;\mu,\sigma) = \sigma^2,\quad \forall \delta
$$
$$
f_\delta(x;\mu,\sigma) \sim \frac1{x^{3+\delta^2}},\quad x\to\infty
$$
The average absolute deviation of the curve is $\delta\sigma$
$$
\int dx\ |x-\mu|f_\delta(x;\mu,\sigma) =
\frac{\Gamma(1/2+\delta^2/2)}{\Gamma(1/2)\Gamma(1+\delta^2/2)}\delta\sigma
$$
Cumulative distribution function
$$
F_\delta(x;\mu,\sigma) = \int_{-\infty}^x\ dx'\ f_\delta(x';\mu,\sigma) =
$$
$$
\frac12 + C_\delta\frac{x-\mu}{\delta\sigma}
{}_2F_1\left(\frac12, \frac{\delta^2+3}2, \frac32, -\frac{(x-\mu)^2}
{\delta^2\sigma^2}\right)
$$
\end{document}
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