If the input is called $x(t)$, then the output $y(t)$ of an ideal (i.e. perfectly linear, with infinite bandwidth) inverting amplifier is:
$$y(t) = - \; A \; x(t-t_d)$$
Where $A > 1$ is the gain of the amplifier and $t_d > 0$ is its propagation delay. The minus sign before the gain is what makes the amplifier inverting.