A Lecture on Submodular Functions I will try to motivate submodular functions with a few examples and then attempt to cast them as the discrete analogues of convex functions. The main results I hope to prove are - Characterize submodular functions in terms of their Lovasz extension. - Submodular intersection theorem. - Frank's discrete separation theorem. The talk is intended for a general audience; the only thing anyone will need to understand the proofs is LP duality.