Constraints of the Dynamic Equations and Lagrangian required by   Superposition of Field
  A general form of the dynamical equations of field is obtained on the requirement this field is a superposable one; hence the constraint on the forms of the Lagrangians is acquired. It shows this requirement requires the continuous transformation group of the Lagrangians of field to be compact, and that All Lagrangians of elementary particles, such as leptons, quarks, photons and gluons, satisfy this requirement.The result of regarding this character as a general property of physical field is discussed. 
X. Sun, Z. Yang