The well-known decomposition of vector fields to solenoidal and irrotationa
l parts, known as the Helmholtz decomposition, is generalized in terms of m
ore general linear operators involving two arbitrary symmetric, positive-de
finite and complete (non-singular) dyadics. It is seen that, in terms of th
e generalized decomposition, potential expansions for the static electric a
nd magnetic fields in anisotropic media can be formed in a straightforward
manner. The decomposition theorem is further generalized in a form applicab
le to the static electromagnetic fields in the most general linear medium (
bi-anisotropic medium) characterized by four medium dyadics. In this case,
the decomposition theorem and potential expressions are presented in a comp
act form in terms of six-vectors.