Monotonicity and supermodularity results for the Erlang loss system

For the Erlang loss system with ss servers and offered load aa, we show that: (i) the load carried by the last server is strictly increasing in aa; (ii) the carried load of the whole system is strictly supermodular on {(s,a)|s=0,1,… and a>0}{(s,a)|s=0,1,… and a>0}.