No Arabic abstract
In this paper, we introduce a new family of period integrals attached to irreducible cuspidal automorphic representations $sigma$ of symplectic groups $mathrm{Sp}_{2n}(mathbb{A})$, which detects the right-most pole of the $L$-function $L(s,sigmatimeschi)$ for some character $chi$ of $F^timesbackslashmathbb{A}^times$ of order at most $2$, and hence the occurrence of a simple global Arthur parameter $(chi,b)$ in the global Arthur parameter $psi$ attached to $sigma$. We also give a characterisation of first occurrences of theta correspondence by (regularised) period integrals of residues of certain Eisenstein series.
We give constraints on existence of $(chi,b)$-factors in the global $A$-parameter of a genuine cuspidal automorphic representation $sigma$ of the metaplectic group in terms of the invariant, lowest occurrence index, of theta lifts to odd orthogonal groups. We also give a refined result that relates the invariant, first occurrence index, to non-vanishing of period integral of residue of Eisenstein series associated to the cuspidal datum $chiotimessigma$. This complements our previous results for symplectic groups.
Following the idea of [GJS09] for orthogonal groups, we introduce a new family of period integrals for cuspidal automorphic representations $sigma$ of unitary groups and investigate their relation with the occurrence of a simple global Arthur parameter $(chi,b)$ in the global Arthur parameter $psi_sigma$ associated to $sigma$, by the endoscopic classification of Arthur ([Art13], [Mok13], [KMSW14]). The argument uses the theory of theta correspondence. This can be viewed as a part of the $(chi,b)$-theory outlined in [Jia14] and can be regarded as a refinement of the theory of theta correspondences and poles of certain $L$-functions, which was outlined in [Ral91].
We derive a precise relation of poles of Eisenstein series associated to the cuspidal datum $chiotimessigma$ and lowest occurrence of theta lifts of a cuspidal automorphic representation $sigma$ of a unitary group, where $chi$ is conjugate self-dual character. We also give a refined result on non-vanishing of periods of Eisenstein series and first occurrence of theta lifts. This gives constraints on existence of $(chi,b)$-factors in the global $A$-parameter of $sigma$.
In this paper a theory of Hecke operators for higher order modular forms is established. The definition of cusp forms and attached L-functions is extended beyond the realm of parabolic invariants. The role of representation theoretic methods is clarified and, motivated by higher order forms, new convolution products of L-functions are introduced.
We investigate the correspondence between holomorphic automorphic forms on the upper half-plane with complex weight and parabolic cocycles. For integral weights at least 2 this correspondence is given by the Eichler integral. Knopp generalized this to real weights. We show that for weights that are not an integer at least 2 the generalized Eichler integral gives an injection into the first cohomology group with values in a module of holomorphic functions, and characterize the image. We impose no condition on the growth of the automorphic forms at the cusps. For real weights that are not an integer at least 2 we similarly characterize the space of cusp forms and the space of entire automorphic forms. We give a relation between the cohomology classes attached to holomorphic automorphic forms of real weight and the existence of harmonic lifts. A tool in establishing these results is the relation to cohomology groups with values in modules of analytic boundary germs, which are represented by harmonic functions on subsets of the upper half-plane. Even for positive integral weights cohomology with these coefficients can distinguish all holomorphic automorphic forms, unlike the classical Eichler theory.