Q: In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.
In physics, this term refers to an even-dimensional system of differential equations in which the generalized momenta are proportional to the derivative of a certain function with respect to the generalized velocities, and vice versa. This adjective describes a non-abelian group whose subgroups are self-conjugate. The Bondy-Chvatal theorem and the Dirac theorem both give conditions necessary for a graph to be described by this word, while an operator named by this word is the Legendre transform of the Lagrangian. For ten points, identify this word which in physics describes an operator that is the sum of the potential and kinetic energies and in computer science a path on a graph which visits every vertex exactly once.
A:
Science