Marieke Dressler (The University of New South Wales) will be giving an applied maths seminar on Wednesday 16th April at 11am in Carslaw 173. Afterwards, we will go to lunch. Students are invited and encouraged to attend to both. Title: New perspectives on signomial programming with a view toward nonlinear dynamics Abstract: Signomials generalize polynomials by allowing arbitrary real exponents, at the expense of restricting the resulting function to the positive orthant. In this talk, I present a novel convex relaxation hierarchy of lower bounds for signomial optimization and discuss how it can be used to study nonlinear dynamics. The hierarchy is derived through the newly-defined concept of signomial rings and a signomial Positivstellensatz based on conditional "sums of arithmetic-geometric exponentials" (SAGE). Numerical examples are provided to illustrate the performance of the hierarchy on problems in chemical engineering and optimal control.