Before revision:  In contrast with the four-currency case, we find that arbitrage operations when d >= 5 currencies are present may appear very unstable, with the exchange rates growing in accordance with the double exponential law !
After revision:  In contrast with the four-currency case, we find that arbitrage operations when d >= 5 or higher-order currency worlds. The key findings are that in a 5-currency world arbitrage sequences may also follow an exponential law as well as display periodicity, but that in higher-order currency worlds a double exponential law !