3.6 Fourierintegrale

$$\delta {1 \over {2 \pi}} \int_{-\infty}^{+\infty}$$ (3.25)

$$\delta_{\pm}^{} {1 \over {2 \pi}} \int_{-\infty}^{+\infty} \Theta \pm$$ (3.26)

$${1 \over x} {1 \over {2 i}} \int_{-\infty}^{+\infty} \varepsilon$$ (3.27)

$$\Theta \pm \pm {1 \over {2 \pi i}} \int_{-\infty}^{+\infty} {{e^{i k x}} \over {k \mp i \varepsilon}} \varepsilon {1 \over {i \pi}} \int_{-\infty}^{+\infty} {1 \over k}$$ (3.28)

$$\delta{^\prime} \int_{-\infty}^{+\infty}$$ (3.29)

$$\delta \vec{x}\, {1 \over {(2\pi)^3}} \int \vec{k}\, \vec{x}\,$$ (3.30)

$$\delta {a \over {2 \pi^2}} \int \vec{k}\, \vec{x}\, {\sin(a k) \over k} \sqrt{\vec{k}^2}$$ (3.31)