Symmetry breaking operators for the restriction of representations of indefinite orthogonal groups O(p, q)

For the pair (G, G '') = (O(p + 1, q + 1), 0(p, q + 1)), we construct and give a complete classification of intertwining operators (symmetry breaking operators) between most degenerate spherical principal series representations of G and those of the subgroup G', extending the work initiated by Kobayashi and Speh [Mem. Amer. Math. Soc. 2015] in the real rank one case where q = 0. Functional identities and residue formula of the regular symmetry breaking operators are also provided explicitly. The results contribute to Program C of branching problems suggested by the first author [Progr. Math. 2015].