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in a probabilitic inventory model the demand lost during stockout events is taken into account as

$1)$ a reduction of the CLS

$2)$ a direct stockout cost referred to the lost sales plus an indirect stockout cost referred to the loss of reputation

$3)$ a stockout cost referred to the ESC by means of a penalty

$4)$ a stockout cost referred to the ESC plus an additional holding cost referred to the unsold products