**Title: **The unreasonable effectiveness of certain mathematical models in practice

**Abstract: **I will discuss three applications where mathematical models have been useful: (1)[Mathematics for Business] Enterprise Inventory Optimization at several Fortune 500/Global 2000 manufacturing firms through the use of discrete-time, stochastic, non-stationary, multi-stage models (real world partner: SmartOps); (2) [Mathematics in entertainment industry] Dynamic scheduling of advertisements in video games (in collaboration with Massive Incorporated, now Microsoft); and (3) [Mathematics to save lives] Distant multi-listing for kidney transplants in the US through the use of affordable on-demand private jets modeled as a selfish routing game on an overcrowded queuing network with abandonments (real world:OrganJet+GuardianWings). I will spend most of my talk on why these models have been useful (when many others have not) rather than on the technical aspects of the specific models or their analyses.