  We focus on the continuous symmetry transformations for the three ($2 +
1$)-dimensional (3D) system of a combination of the free Abelian 1-form and
2-form gauge theories within the framework of Becchi-Rouet-Stora-Tyutin (BRST)
formalism. We establish that this combined system is a tractable
field-theoretic model of Hodge theory. The symmetry operators of our present
theory provide the physical realizations of the de Rham cohomological operators
of differential geometry at the algebraic level. Our present investigation is
important in the sense that, for the first time, we are able to establish an
odd dimensional (i.e. $D = 3$) field-theoretic system to be an example for
Hodge theory (besides earlier works on a few interesting ($0 + 1$)-dimensional
toy models as well as a set of well-known ${\mathcal N} = 2$ SUSY quantum
mechanical systems of physical interest). For the sake of brevity, we have not
taken into account the 3D Chern-Simon term for the Abelian 1-form gauge field
in our theory which allows the mass and gauge-invariance to co-exist together.
