The notation "f⁻¹" represents the inverse of a function f. An inverse function essentially reverses the effect of the original function. If f takes an input x and produces an output y, then the inverse function f⁻¹ takes y and returns it back to x. For a function to have an inverse, it must be one-to-one, meaning each output corresponds to exactly one input. This ensures that the inverse function is well-defined. In mathematical terms, if f(x) = y, then f⁻¹(y) = x.