{
  "abstract": "We introduce relative $h$-diagonals for crossed products $A\\rtimes_αΓ$ by discrete groups, which are positive-form approximate diagonals in the Haagerup tensor product taken relative to $A$. We show that $α$ is amenable if and only if $A\\rtimes_αΓ$ admits a relative $h$-diagonal, an analogue of Johnson's theorem for $L^{1}(G)$.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.30821",
  "author_total": 1,
  "authors": [
    {
      "name": "Zhengyu Fu"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/29zb8tspssfhb.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.30821",
  "fulltext_url": null,
  "id": "29zb8tspssfhb",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.30821",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "math.OA"
    ],
    [
      "openalex",
      "2610|Advanced Operator Algebra Research"
    ]
  ],
  "openalex": "W7223403738",
  "pdf_url": "https://arxiv.org/pdf/2610.30821",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-22",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/29zb8tspssfhb.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:34:38Z",
      "native_id": "2610.30821",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.30821"
    }
  ],
  "subjects": [
    {
      "field": "mathematics",
      "origin": "arxiv:math.OA",
      "subfield": "analysis-pdes"
    }
  ],
  "title": "An Approximate-Diagonal Characterization of Amenable Actions on C*Algebras",
  "title_text": "An Approximate-Diagonal Characterization of Amenable Actions on C*Algebras",
  "type": "preprint",
  "updated_at": "2026-10-30T12:34:38Z",
  "url": "https://research.draconitic.com/paper/29zb8tspssfhb",
  "venue": "arXiv",
  "versions": []
}