Consider two real valued functions $f$ and $g$ given by $$f(x)=\frac{x}{x-1} \; \text{for } x>1, \quad \text{and }\quad g(x)=7-x^{3} \; \text{for } x \in \mathbb{R}.$$ Which of the following statements about inverse functions is true?
- Neither $f^{-1}$ nor $g^{-1}$ exists
- $f^{-1}$ exists, but not $g^{-1}$
- $f^{-1}$ does not exist, but $g^{-1}$ does
- Both $f^{-1}$ and $g^{-1}$ exist.