2019/12/23 by Dubravka Ban, Ban, Dubravka, Matthias Strauch +1
Mathematics · #11S37 #20G25 #22E50 #Advanced Algebra and Geometry #Algebraic Geometry and Number Theory #FOS: Mathematics #Representation Theory (math.RT) #advanced mathematical theories
paper · pdf · doi:10.48550/arxiv.1912.11125
openalex publication_date 2019/12/23 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We consider the restriction to SL2(\mathbb Qp) of an irreducible p-adic unitary Banach space representation Π of GL2(\mathbb Qp). If Π is associated, via the p-adic local Langlands correspondence, to an absolutely irreducible 2-dimensional Galois representation ψ, then the restriction of Π decomposes as a direct sum of r ≤ 2 irreducible representations. The main result of this paper is that r is equal to the cardinality s of the centralizer in PGL2 of the projective Galois representation ψ associated to ψ, and the restriction is multiplicity-free, except if ψ is triply-imprimitive, in which case the restriction of Π is a direct sum of two equivalent representations. From this result we derive a classification of absolutely irreducible p-adic unitary Banach space representations of SL2(\mathbb Qp).