Инвариантные подпространства в функциональных пространствах медленного роста на световом конусе в $R^{3}$

We describe the structure of closed linear subspaces in tempered topological vector function spaces on the light cone $X$ in $R^{3}$ that are invariant with respect to the natural quasiregular representation of the group $R\oplus SO_{0}(1,2)$. In particular, we obtain a description of the irreducible and indecomposable invariant subspaces. The class of function spaces under consideration include, in particular, the space $S'(X)$ of all tempered distributions on $X$.