  Dragan and Ekert in the paper (2020 \emph{New. J. Phys.} \textbf{22} 033038)
presented 'quantum principle of relativity' (QPR) based on Galilean principle
of relativity, which involves both superluminal $G_S$ and subluminal $G_s$
families of observers and argue that then they are considered on the same
footing it 'implies the emergence of non-deterministic dynamics, together with
complex probability amplitudes and multiple trajectories.'. Here we discuss QPR
in the context of Heisenberg's classification of the fundamental physical
theoretical models under the role universal constants of nature: Planck's
constant $h$ and speed of light $c$. We point out that both the superluminal
and subluminal branches are separable in the sense that there is no
mathematical coherent formalism that connect both branches. This, in
particular, implies that the QPR is incomplete.
