  Invariant tensors play an important role in gauge theories, for example, in
dualities of N=1 gauge theories. However, for theories with fields in
representations larger than the fundamental, the full set of invariant tensors
is often difficult to construct. We present a new approach to the construction
of these tensors, and use it to find the complete set of invariant tensors of a
theory of SO(3) with fields in the symmetric tensor representation.
