Differential symmetry breaking operators for the pair $(\operatorname{GL}_{n+1}(\mathbb{R}),\operatorname{GL}_n(\mathbb{R}))$
Jonathan Ditlevsen, Quentin Labriet
TL;DR
This work analyzes differential symmetry breaking operators between principal series of $(\mathrm{GL}_{n+1}(\mathbb{R}),\mathrm{GL}_n(\mathbb{R}))$ by employing a source operator approach to generate explicit intertwiners. For generic induction parameters, the authors construct a comprehensive basis of DSBOs as composites of source operators and restriction maps, and prove these exhaust all possibilities; these operators also appear as residues of a Meromorphic SBO family, linking algebraic and analytic viewpoints. The paper further provides a full classification in the non-generic case when $n=2$, revealing a multiplicity-two phenomenon for certain one-point supports and detailing alternative constructions of DSBO bases. Together, these results give a detailed, parameter-sensitive picture of how representations restrict along the pair $(G,H)$ and establish a residue-bridge between explicit differential operators and holomorphic families of intertwiners with explicit $e$-function factors. The findings advance the understanding of higher-rank symmetry breaking by reducing the problem to canonical source-operator data and Bernstein–Sato identities, with potential applications to explicit branching problems and automorphic contexts.$
Abstract
In this article we study differential symmetry breaking operators between principal series representations induced from minimal parabolic subgroups for the pair $(\operatorname{GL}_{n+1}(\mathbb{R}),\operatorname{GL}_n(\mathbb{R}))$. Using the source operator philosophy we construct such operators for generic induction parameters of the representations and establish that this approach yields all possible operators in this setting. We show that these differential operators occur as residues of a family of symmetry breaking operators that depends meromorphically on the parameters. Finally, in the $n=2$ case we classify and construct all differential symmetry breaking operators for any parameters, including the non-generic ones.
