We present a counterexample to a lower bound for the power domination number given in Liao, Power domination with bounded time constraints, J. Comb. Optim. 31 (2016)725-742. We also define the power propagation time, using the power domination propagation ideas in Liao and the (zero forcing) propagation time in Hogben et al, Propagation time for zero forcing on a graph, Discrete Appl. Math.160 (2012) 1994-2005.
@article{arxiv.1512.06413,
title = {Power propagation time and lower bounds for power domination number},
author = {Daniela Ferrero and Leslie Hogben and Franklin H. J. Kenter and Michael Young},
journal= {arXiv preprint arXiv:1512.06413},
year = {2016}
}