document: Note on `` Deterministic inventory lot-size models under inflation with shortages and deterioration for fluctuating demand '' by Yang et al For original paper see H.-L . Yang et al. , ibid. , vol .48 , p.144-58 -LRB- 2001 -RRB- . Yang et al. extended the lot-size models to allow for inflation and fluctuating demand . For this model they proved that the optimal replenishment schedule exists and is unique . They also proposed an algorithm to find the optimal policy . The present paper provides examples , which show that the optimal replenishment schedule and consequently the overall optimal policy may not exist
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