{
  "abstract": "Let $E/F$ be a CM extension and let $m\\geq2$ be an even integer. Starting from the odd-degree Hermitian Ikeda lift of degree $m+1$ constructed by Yamana, we construct a Hermitian Ikeda lift of degree $m$ from the theta components of its first Fourier-Jacobi coefficient. We determine its global Arthur parameter and its local constituents at every finite place. Using the global multiplicity formula for unitary groups, we obtain an explicit multiplicity-free decomposition of the resulting representation of $\\mathrm{U}_{m.m}(\\mathbb{A}_{F,\\mathbf{h}})$ and show that its isomorphism class is independent of the Fourier-Jacobi index. When $F=\\mathbb{Q}$, we compare Fourier coefficients and identify the construction with Ikeda's even-degree Hermitian lift.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.17396",
  "author_total": 1,
  "authors": [
    {
      "name": "Nobuki Takeda"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/5f3vb9y8gp59y.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.17396",
  "fulltext_url": null,
  "id": "5f3vb9y8gp59y",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.17396",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "math.NT"
    ],
    [
      "openalex",
      "2610|Advanced Algebra and Geometry"
    ]
  ],
  "openalex": "W7213392971",
  "pdf_url": "https://arxiv.org/pdf/2609.17396",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-15",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/5f3vb9y8gp59y.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:21:45Z",
      "native_id": "2609.17396",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.17396"
    }
  ],
  "subjects": [
    {
      "field": "mathematics",
      "origin": "arxiv:math.NT",
      "subfield": "algebra-number-theory"
    }
  ],
  "title": "Even-degree Hermitian Ikeda lifts via Fourier-Jacobi descent",
  "title_text": "Even-degree Hermitian Ikeda lifts via Fourier-Jacobi descent",
  "type": "preprint",
  "updated_at": "2026-10-30T12:21:45Z",
  "url": "https://research.draconitic.com/paper/5f3vb9y8gp59y",
  "venue": "arXiv",
  "versions": []
}