Final answer:
The first milestone in inventory management models dates back to 1913 with the development of the Economic Order Quantity by Ford W. Harris. Later enhancements include the Hotelling Model for site location and expanded principles of scientific management in inventory systems.
Step-by-step explanation:
The first mathematical model for inventory management was not conceived at a specific pinpointed time; however, a significant milestone in inventory management came with the development of Economic Order Quantity (EOQ), which was introduced by Ford W. Harris in 1913. This model is fundamental in the realm of inventory management and operations. Further advancements in inventory models were made by the likes of Harrold Hotelling, who developed the Hotelling Model for location in the late 1920s. It wasn't until after the first half of the 20th century that more sophisticated models and systems of inventory management started to evolve, influenced by the principles of scientific management or 'Taylorism', introduced by Frederick Winslow Taylor in 1911, that sought out efficiency in industrial operations.
Modern inventory models often include complex mathematical formulas and computations because they have to consider multiple factors such as holding costs, ordering costs, and demand patterns to optimize the inventory levels. They can vary from basic models like the EOQ to more complex ones that incorporate dynamic and uncertain demand, lead times, and perishability.