  A formal proof to relate the concept of electromagnetic local density of
states (LDOS) to the electric and magnetic dyadic Green's functions is
provided. The expression for LDOS is obtained by relating the electromagnetic
energy density at any location in a medium at uniform temperature $T$ to the
electric and magnetic dyadic Green's functions. With this the concept of LDOS
is also extended to material media. The LDOS is split into two terms -- one
that originates from the energy density in an infinite, homogeneous medium and
the other that takes into account scattering from inhomogenieties. The second
part can always be defined unambiguously, even in lossy materials. For lossy
materials, the first part is finite only if spatial dispersion is taken into
account.
