Green's Function
The Green's function for the d'Alembertian is defined by the equation
where is the Dirac delta function and and are two points in Minkowski space.
A special solution is given by the retarded Green's function which corresponds to signal propagation only forward in time
where is the Heaviside step function.
Read more about this topic: D'Alembert Operator
Famous quotes containing the words green and/or function:
“And nothing I cared, at my sky blue trades, that time allows
In all his tuneful turning so few and such morning songs
Before the children green and golden
Follow him out of grace.”
—Dylan Thomas (1914–1953)
“Of all the inhabitants of the inferno, none but Lucifer knows that hell is hell, and the secret function of purgatory is to make of heaven an effective reality.”
—Arnold Bennett (1867–1931)