customer demand at retailer k in period t, it is an uncertain
variable and is short for dk(t).
Pk(t): unit retail price to the customer of retailer k in period t, is
shortened as pk.
hk(t): unit holding cost per period of unsold product of retailer k,
is shortened as hk.
uk(t): unit shortage cost of retailer k.
Fk(q): probability density function of customer demand at retailer
k.
/k(t): order price of the commodity for retailer k in period t; for
simplification, it is shorten as /k and let /k ¼ /ik; 8i 2 I. Where
/ik: the average wholesale price of all suppliers to retailer k.
zup: The maximal possible retail amount of the retailer.