@wikipedia
\mbox{erfc}(x) = 1- erf(x) = \frac{1}{\sqrt{\pi}} \, \int_x^{\infty} e^{-\zeta^2} d \zeta
Fig. 1. Erfc(x) sample graph for the real argument
Error Function (Erf)
https://mathworld.wolfram.com/Erfc.html
