A mathematical technique used to find values of variables that minimize or maximize an objective function while satisfying equality constraints.

a mathematical "function" that involves various different forms of energy

A Lagrangian \mathcal{L}[\varphi_i] of a dynamical system, named after Joseph Louis Lagrange, is a function of the dynamical variables \ \varphi_i(s) and concisely describes the equations of motion of the system.

points, or L1, L2, L3, L4, L5: see libration points

Hydrodynamic scheme where calculational mesh moves with materials.