Hereby we shall consider the terms γi ðxiÞ as given functions. In the source term, in the right-hand side of (6a), B(t) stands for the birthrate function, and δðxiÞ is the Dirac function, suggesting that new particles are born at a negligible size.
Hereby we shall consider the terms γiðxiÞ as given functions. In thesource term, in the right-hand side of (6a), B(t) stands for the birthratefunction, and δðxiÞ is the Dirac function, suggesting that new particlesare born at a negligible size.