“… 4 As is common in the literature that considers the competition between traditional retailers and location-irrelevant retailers (Balasubramanian, 1998 , Bouckaert, 2000 , Nakayama, 2009 , Colombo and Hou, 2019 , Colombo and Matsushima, 2020 , Guo and Lai, 2014 and 2017 ), we consider only one location-irrelevant (online) retailer. Indeed, several online retailers could generate price undercutting and zero profits.…”