{
  "abstract": "Let $\\varphi:G\\twoheadrightarrow Q$ be an epimorphism of finitely presented groups. We characterize when $\\varphi$ is induced, under fixed markings, by continuous Gromov--Hausdorff approximation maps for a sequence of metrics on a fixed closed manifold, with a uniform lower Ricci bound, bounded diameter and a positive lower volume bound. A realization with a compact semilocally simply connected limit exists in some dimension if and only if $\\ker\\varphi$ is finitely normally generated by finite-order elements of $G$. Every such epimorphism has a realization on a fixed closed oriented four-manifold with constant positive volume, two-sided Ricci bounds and uniformly bounded $L^2$ curvature. The limit is an orbifold with one isolated flat singularity for each nonidentity element in a chosen finite list of finite-order normal generators of the kernel. We construct two resolutions of one orbifold whose fundamental groups are Thompson's group $V$ and the trivial group, and whose scalar eigenvalues have the same limit at each fixed index. We also give a five-dimensional nonnegative-Ricci sequence with infinite dihedral fundamental group and simply connected limit. Finally, in every fixed dimension, under uniform lower Ricci, diameter and volume bounds, a heat integral comparing a manifold with its universal cover diverges exactly when the homotopy systole tends to zero.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": null,
  "author_total": 1,
  "authors": [
    {
      "name": "Anass Nifa"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/9w134qybzhejw.bib",
  "cited_by": 0,
  "doi": "10.5281/zenodo.22770177",
  "fulltext_url": null,
  "id": "9w134qybzhejw",
  "issns": [],
  "landing_url": "https://hal.science/hal-05769943v1",
  "language": "en",
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "hal",
      "0.math"
    ],
    [
      "hal",
      "1.math.math-dg"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://hal.science/hal-05769943/document",
  "pmcid": null,
  "pmid": null,
  "published": "2026-05-25",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/9w134qybzhejw.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:43Z",
      "native_id": "hal-05769943",
      "source": "hal",
      "url": "https://hal.science/hal-05769943v1"
    }
  ],
  "subjects": [
    {
      "field": "mathematics",
      "origin": "hal:1.math.math-dg",
      "subfield": "geometry-topology"
    }
  ],
  "title": "Fundamental-group epimorphisms in noncollapsed Ricci limits",
  "title_text": "Fundamental-group epimorphisms in noncollapsed Ricci limits",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:43Z",
  "url": "https://research.draconitic.com/paper/9w134qybzhejw",
  "venue": "HAL",
  "versions": []
}