# Discrete Fourier transform - Norms of complex input signals and their transformation

Given a signal $$\mathbf{z} \in \mathbb{C}^n$$ and its Discrete Fourier transform $$\hat{\mathbf{z} }$$, does $$||\mathbf{z}|| = ||\hat{\mathbf{z} }||$$ hold?

The question is given to me like this with no additional details. Information about what kind of norm is also not given. Does anyone have an idea what the question might be looking for?