变分原理 biànfēnyuánlǐ variational principle Origin Definitions Defs Strokes Stroke Words Sentences Sents 变分 變分 biànfēn variation a change in the form of a function, used in the calculus of variations; deformation原理 yuánlǐ principle a basic truth, law, or theory that serves as the foundation for a system of belief or behavior; scientific principle or tenet