Yuanqing Cai

Postdoctoral Fellow
Department of Mathematics
The Weizmann Institute of Science
Herzl 234, Rehovot 7610001
Email: yuanqing[dot]cai[at]weizmann[dot]ac[dot]il
Office: Goldsmith Building, Room 212


I recently received my PhD from Boston College, under the supervision of Solomon Friedberg.

I'm interested in number theory and representation theory. In particular, my interests include:

Publications and Preprints

  1. (with S. Friedberg and E. Kaplan) Doubling constructions: local and global theory, with an application to global functoriality for non-generic cuspidal representations. (arXiv)

  2. This paper is the natural continuation of item 2 and 3. We develop local and global theory of the generalized doubling integrals in item 2. This allows us to establish liftings for spaces of automorphic forms (first proved by Arthur) without using the trace formula. In this preprint, we treat symplectic, special orthogonal and general spin groups.

  3. (with S. Friedberg, D. Ginzburg and E. Kaplan) Doubling constructions and tensor product L-functions: the linear case. (arXiv)

  4. This is the first in a series of papers on the work promised in the research announcement below. In this preprint, we treat symplectic and even orthogonal groups. Subsequent papers (in preparation) will treat odd orthogonal and general spin groups, the metaplectic covering version of these integrals, and applications to functoriality coming from combining this work with the converse theorem (and independent of the trace formula).

  5. (with S. Friedberg, D. Ginzburg and E. Kaplan) Doubling constructions for covering groups and tensor product L-functions, preprint. Research announcement on the arxiv, here.

  6. In the 1980's, Piatetski-Shapiro and Rallis discovered a family of Rankin-Selberg integrals for the classical groups that did not rely on Whittaker models. This is the so-called doubling method. It grew out of Rallis' work on the inner products of theta lifts -- the Rallis inner product formula. In this work, we give a generalization of the doubling method. We present a family of integrals representing tensor product L-functions of classical groups with general linear groups. Our construction is uniform over all classical groups and their non-linear coverings, and is applicable to all cuspidal representations.

  7. Braidless weights, minimal representatives and the Weyl group multiple Dirichlet series. (PDF.)

  8. For a semisimple Lie algebra admitting a good enumeration, we prove a parameterization for the elements in its Weyl group. As an application, we give coordinate-free comparison between the crystal graph description (when it is known) and the Lie-theoretic description of the Weyl group multiple Dirichlet series in the stable range.

  9. Fourier coefficients for degenerate Eisenstein series and the descending decomposition. (PDF, arXiv, journal.) To appear in Manuscripta Math.

  10. For type A root systems, we generalize a lemma of Casselman-Shalika. We use it to calculate the unipotent orbits attached to degenerate Eisenstein series on general linear groups. This confirms a conjecture of David Ginzburg.

  11. Fourier coefficients for Theta representations on covers of general linear groups. (PDF, arXiv, journal.) To appear in Trans. Amer. Math. Soc.
    Video presentation.

  12. In this paper we determine the unipotent orbits attached to the theta representations on covers of general linear groups. In some special cases, we show that the theta representations support certain (degenerate) types of unique functionals. One of these unique functionals is used in item 3.


Research Talks


Here is a picture of the
alcove of G2, under the action of the affine Weyl group.