Divergence

In mathematics, divergence is a differential operator that associates a vector field with a scalar field. In a vector field, each point of the field is associated with a vector; in a scalar field, each point of the field is associated with a scalar. 
Given a vector field formula_1, the divergence of formula_1 can be written as formula_3 or formula_4, where formula_5 is the gradient and formula_6 is the dot product operation. 
Divergence is used to formulate Maxwell's equations and the continuity equation.