  Madsen et al. [arXiv:1307.2577] claim that one-dimensional insulating
crystals and one-dimensional insulating quasicrystals are topologically
equivalent and, thus, trivial. In this comment, we clarify that in topological
classification of one-dimensional systems, quasiperiodicity plays a role
similar to that of a symmetry. Hence, periodic systems are out of the
quasiperiodic topological space, and the equivalence between quasicrystals and
crystals becomes immaterial.
