{
  "version": "v0-step2026",
  "step": 2026,
  "generated_at": "2026-09-13T20:13:21.081Z",
  "purpose": "Documentation of academic estimate ranges for mismatch cases identified in STEP 2024 Wikidata date cross-verify. All entries backed by WebFetch primary sources (Wikipedia EN + Wikidata).",
  "discipline": "Wikipedia + Wikidata are secondary/tertiary sources; provenance.level stays \"unverified\". lifespan.born_estimates + died_estimates document alt estimates without overriding seed values.",
  "mismatch_summary": {
    "born_mismatches": 6,
    "died_mismatches": 2,
    "hironaka_death_verified": true
  },
  "estimates": {
    "person:pythagoras": {
      "born_estimates": [
        {
          "year": -570,
          "circa": true,
          "source": "Wikipedia EN + seed",
          "note": "Aristoxenus に 基づく c.570 BC estimate (Polycrates 40 歳離 Samos 逆算)"
        },
        {
          "year": -582,
          "circa": true,
          "source": "Wikidata Q10261",
          "note": "WD alternate estimate"
        }
      ]
    },
    "person:euclid": {
      "born_estimates": [
        {
          "year": -325,
          "circa": true,
          "source": "Wikipedia EN",
          "note": "Some scholars estimate around 330 or 325 BC; others refrain from speculating"
        },
        {
          "year": -330,
          "circa": true,
          "source": "Wikipedia EN alt"
        },
        {
          "year": -333,
          "circa": true,
          "source": "Wikidata Q8747",
          "note": "WD estimate"
        }
      ],
      "died_estimates": [
        {
          "year": -270,
          "circa": true,
          "source": "Wikipedia EN",
          "note": "Speculated died c.270 BC"
        },
        {
          "year": -285,
          "circa": true,
          "source": "Wikidata Q8747",
          "note": "WD estimate"
        }
      ]
    },
    "person:apollonius-of-perga": {
      "born_estimates": [
        {
          "year": -240,
          "circa": true,
          "source": "Wikipedia EN",
          "note": "Modern consensus c.240 BC (Ptolemy III Euergetes reign 246-222 BC 統治期 に 誕生 or 教育)"
        },
        {
          "year": -260,
          "circa": true,
          "source": "Wikipedia EN earlier",
          "note": "Earlier scholars favored c.260 BC"
        },
        {
          "year": -262,
          "circa": true,
          "source": "Wikidata Q180109",
          "note": "WD estimate"
        }
      ]
    },
    "person:hypatia-of-alexandria": {
      "born_estimates": [
        {
          "year": 350,
          "circa": true,
          "source": "seed + Wikipedia EN range low",
          "note": "Wikipedia: birth range 350-370 AD 内 の 低 end"
        },
        {
          "year": 360,
          "circa": true,
          "source": "Wikidata Q11903",
          "note": "WD estimate = Wikipedia range 中央値"
        },
        {
          "year": 370,
          "circa": true,
          "source": "Wikipedia EN range high",
          "note": "Wikipedia: 「Hypatia's exact year of birth is still under debate」"
        }
      ]
    },
    "person:pierre-de-fermat": {
      "born_estimates": [
        {
          "year": 1601,
          "circa": false,
          "source": "Wikipedia EN primary + Wikidata Q75655",
          "note": "Modern research primary: 「Most sources give Fermat's birth year as 1601」 (August 17, 1601)"
        },
        {
          "year": 1607,
          "circa": false,
          "source": "seed (earlier historical claim)",
          "note": "Wikipedia: 「Some sources give ... 1607, however, recent research suggests this was the year a half-brother called Piere was born」 = 1607 は 異腹兄弟の 生年 で 1601 が Pierre 本人"
        }
      ]
    },
    "person:qin-jiushao": {
      "born_estimates": [
        {
          "year": 1202,
          "circa": true,
          "source": "Wikipedia EN + seed",
          "note": "Wikipedia: 「ca. 1202-1261」"
        },
        {
          "year": 1208,
          "circa": true,
          "source": "Wikidata Q565225",
          "note": "WD alternate estimate"
        }
      ]
    },
    "person:leonardo-fibonacci": {
      "died_estimates": [
        {
          "year": 1240,
          "circa": true,
          "source": "Wikidata Q8763 + Wikipedia EN range low",
          "note": "Wikipedia: 「c.1240-50」 range の 低 end、 「Fibonacci is thought to have died between 1240 and 1250」"
        },
        {
          "year": 1250,
          "circa": true,
          "source": "seed + Wikipedia EN range high",
          "note": "Wikipedia range の 高 end"
        }
      ]
    }
  },
  "hironaka_death_verification": {
    "person_id": "person:heisuke-hironaka",
    "died": 2026,
    "died_date_specific": "2026-03-18 (東京)",
    "age_at_death": 94,
    "primary_sources": [
      "Asahi Shimbun Digital, 2026-03-18: https://www.asahi.com/articles/ASV3L20SXV3LUTFL00QM.html",
      "Jiji.com, 2026-03-19: https://www.jiji.com/jc/article?k=2026031901047&g=soc",
      "The New York Times, 2026-03-25 (Kenneth Chang obituary)"
    ],
    "verified_via": "WebFetch Wikipedia EN + Wikidata Q183373 (both cite the primary sources above)",
    "provenance_change": "lifespan.died -1 (living) → 2026 (verified), provenance.refs populated with 3 primary sources, provenance.fields_verified = [\"died\"] (died is refs-backed; other fields still tertiary anchor only)"
  }
}