Function: erfc
Section: transcendental
C-Name: gerfc
Prototype: Gp
Help: erfc(x): complementary error function.
Doc: complementary error function, analytic continuation of
$(2/\sqrt\pi)\int_x^\infty e^{-t^2}\,dt = \kbd{incgam}(1/2,x^2)/\sqrt\pi$,
where the latter expression extends the function definition from real $x$ to
all complex $x \neq 0$.