{
  "id": "helfrich85-enumeration",
  "categoryId": "svp-enumeration",
  "paperId": "helfrich-1985",
  "date": "1985-12-31",
  "datePrecision": "year",
  "year": 1985,
  "time": {
    "coefficient": 0.5,
    "expression": "n^{n/2+o(n)}"
  },
  "space": {
    "coefficient": null,
    "expression": "poly(input size)"
  },
  "tags": [
    "enumeration",
    "polynomial space",
    "n log n scale"
  ],
  "review": {
    "status": "source-checked"
  },
  "certificate": {
    "status": "not-provided",
    "lean": null
  },
  "notes": "The n^{n/2+o(n)} SVP refinement is explicitly attributed to Helfrich 1985 by Hanrot–Stehlé 2007. That later primary research paper was read; the original Helfrich theorem was not retrieved. This row records the checked historical attribution, rather than claiming an independent reading of the 1985 proof. The scale is n log n and must remain separate from singly exponential SVP.",
  "extra": {
    "norm": "Euclidean ℓ₂",
    "success": "Deterministic exact algorithm",
    "model": "Classical; polynomial input-size factors suppressed"
  },
  "evidence": {
    "url": "https://perso.ens-lyon.fr/damien.stehle/downloads/crypto2007.pdf",
    "locator": "Introduction, PDF p. 2; §3.3; reference [13]",
    "sourceVersion": "CRYPTO 2007 author preprint; checked historical attribution"
  }
}