Comment on 'Quantum principle of relativity'

Abstract: 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.