In this presentation the speaker will briefly outline some recent results in a number of separate and yet not unrelated topics. The problems covered will include:
1. Tradeoffs between discounting and averaging in discrete time stochastic, dynamic optimisation models over an infinite time horizon
2. Hamiltonian Cycle and Travelling Salesman problems as singularly perturbed controlled Markov chains
3. Stationary distributions of singularly perturbed Markov chains
4. Time scales and singularly perturbed systems
5. An integrated model of the enhanced greenhouse effect; stabilisation at equilibrium and uncertainty propagation.