In abstract terms, the Calculus of Variations is a subject concerned with max/min problems for a real-valued function of several variables. Given a vector space V and a function Φ:V → R, we explore the theory and practice of minimizing Φ[x] over x ∈ V . Additional interest and power comes from allowing • dim(V ) = +∞, • constrained minimization, where the choice variable x must lie in some prea...