{
  "schema": "groups.qft.org/entity/2",
  "versions": {
    "schema": "2.0.0",
    "dataset": "2026.11-workbench.4",
    "application": "6.0.0",
    "algorithm": "groups-workbench-4.0.0",
    "released": "2026-11-08"
  },
  "canonicalURL": "https://groups.qft.org/atlas/groups/q-16/",
  "entity": {
    "id": "group:q-16",
    "slug": "q-16",
    "name": "Generalized quaternion group of order sixteen",
    "symbol": "Q₁₆",
    "category": "finite",
    "level": "reference",
    "aliases": [
      "QuaternionGroup(16)",
      "Dic4",
      "Dic(4)"
    ],
    "searchTerms": [
      "Generalized quaternion group of order sixteen",
      "Q₁₆",
      "QuaternionGroup(16)",
      "Dic4",
      "Dic(4)",
      "SmallGroup(16,9)"
    ],
    "tags": [
      "Finite reference",
      "Nonabelian"
    ],
    "summary": "A generalized quaternion group with four real singlets, one real doublet and two quaternionic doublets.",
    "definition": "The group with a⁸ = 1, x² = a⁴ and xax⁻¹ = a⁻¹.",
    "definitionEvidence": [
      {
        "source": "finite-groupnames-q-16",
        "locator": "Heading; Aliases; Generators and relations"
      }
    ],
    "properties": [
      {
        "key": "order",
        "label": "Order",
        "value": "16",
        "evidence": [
          {
            "source": "finite-groupnames-q-16",
            "locator": "Heading: order"
          }
        ],
        "assumptions": []
      },
      {
        "key": "center",
        "label": "Center",
        "value": "C₂",
        "evidence": [
          {
            "source": "finite-groupnames-q-16",
            "locator": "Centre"
          }
        ],
        "assumptions": []
      },
      {
        "key": "abelian",
        "label": "Abelian",
        "value": "No",
        "evidence": [
          {
            "source": "finite-groupnames-q-16",
            "locator": "Commutator; character table"
          }
        ],
        "assumptions": []
      },
      {
        "key": "simple",
        "label": "Simple",
        "value": "No",
        "evidence": [
          {
            "source": "finite-groupnames-q-16",
            "locator": "Chief series; Centre"
          }
        ],
        "assumptions": []
      },
      {
        "key": "irreps",
        "label": "Ordinary complex irreducibles",
        "value": "1, 1, 1, 1, 2, 2, 2",
        "evidence": [
          {
            "source": "finite-groupnames-q-16",
            "locator": "Character table: identity column and real/complex/symplectic annotations"
          },
          {
            "source": "gap",
            "locator": "Irr and section 71.12-5 Indicator"
          }
        ],
        "assumptions": [
          "Characteristic zero",
          "Finite-dimensional irreducibles over C",
          "Dimensions listed with multiplicity"
        ]
      },
      {
        "key": "smallgroups-id",
        "label": "GAP SmallGroups ID",
        "value": "SmallGroup(16,9)",
        "evidence": [
          {
            "source": "finite-groupnames-q-16",
            "locator": "Aliases; GAP/Magma code by ID"
          }
        ],
        "assumptions": []
      }
    ],
    "sections": [
      {
        "id": "representations",
        "title": "Representation scope",
        "paragraphs": [
          {
            "text": "The complete list of ordinary complex irrep dimensions is given above. Labels ρ1, ρ2, … follow the cited GroupNames character-table row order; they are local labels, not dimension-based identities.",
            "evidence": [
              {
                "source": "finite-groupnames-q-16",
                "locator": "Character table"
              }
            ],
            "assumptions": []
          },
          {
            "text": "Real, Complex and Quaternionic refer to Frobenius–Schur type (+1, 0, −1). The linked character table provides additional data; this entry does not supply matrices or a modular representation catalogue.",
            "evidence": [
              {
                "source": "finite-groupnames-q-16",
                "locator": "Character table: identity column and real/complex/symplectic annotations"
              },
              {
                "source": "gap",
                "locator": "Irr and section 71.12-5 Indicator"
              }
            ],
            "assumptions": []
          }
        ]
      }
    ],
    "relationships": [
      {
        "type": "member-of",
        "target": "family:finite-dicyclic",
        "label": "Family",
        "evidence": [
          {
            "source": "finite-groupnames-q-16",
            "locator": "Heading; Aliases"
          }
        ]
      },
      {
        "type": "central-quotient",
        "target": "group:d-8",
        "label": "Q₁₆ / C₂ ≅ D₈",
        "evidence": [
          {
            "source": "finite-groupnames-q-16",
            "locator": "Centre: quotient D₄ in the order-eight convention"
          }
        ]
      }
    ],
    "capabilities": [],
    "kind": "group",
    "data": {
      "category": "finite",
      "order": "16",
      "abelian": false,
      "simple": false,
      "irreps": {
        "category": "ordinary-complex",
        "complete": true,
        "labels": [
          "ρ1",
          "ρ2",
          "ρ3",
          "ρ4",
          "ρ5",
          "ρ6",
          "ρ7"
        ],
        "dimensions": [
          1,
          1,
          1,
          1,
          2,
          2,
          2
        ],
        "reality": [
          "Real",
          "Real",
          "Real",
          "Real",
          "Real",
          "Quaternionic",
          "Quaternionic"
        ]
      }
    }
  },
  "claims": [
    {
      "id": "group:q-16#definition",
      "subject": "group:q-16",
      "key": "definition",
      "label": "Definition",
      "value": "The group with a⁸ = 1, x² = a⁴ and xax⁻¹ = a⁻¹.",
      "evidence": [
        {
          "source": "finite-groupnames-q-16",
          "locator": "Heading; Aliases; Generators and relations"
        }
      ],
      "assumptions": [],
      "reviewStatus": "pending-expert-review",
      "revision": "2026.11-workbench.4"
    },
    {
      "id": "group:q-16#order",
      "subject": "group:q-16",
      "key": "order",
      "label": "Order",
      "value": "16",
      "evidence": [
        {
          "source": "finite-groupnames-q-16",
          "locator": "Heading: order"
        }
      ],
      "assumptions": [],
      "reviewStatus": "pending-expert-review",
      "revision": "2026.11-workbench.4"
    },
    {
      "id": "group:q-16#center",
      "subject": "group:q-16",
      "key": "center",
      "label": "Center",
      "value": "C₂",
      "evidence": [
        {
          "source": "finite-groupnames-q-16",
          "locator": "Centre"
        }
      ],
      "assumptions": [],
      "reviewStatus": "pending-expert-review",
      "revision": "2026.11-workbench.4"
    },
    {
      "id": "group:q-16#abelian",
      "subject": "group:q-16",
      "key": "abelian",
      "label": "Abelian",
      "value": "No",
      "evidence": [
        {
          "source": "finite-groupnames-q-16",
          "locator": "Commutator; character table"
        }
      ],
      "assumptions": [],
      "reviewStatus": "pending-expert-review",
      "revision": "2026.11-workbench.4"
    },
    {
      "id": "group:q-16#simple",
      "subject": "group:q-16",
      "key": "simple",
      "label": "Simple",
      "value": "No",
      "evidence": [
        {
          "source": "finite-groupnames-q-16",
          "locator": "Chief series; Centre"
        }
      ],
      "assumptions": [],
      "reviewStatus": "pending-expert-review",
      "revision": "2026.11-workbench.4"
    },
    {
      "id": "group:q-16#irreps",
      "subject": "group:q-16",
      "key": "irreps",
      "label": "Ordinary complex irreducibles",
      "value": "1, 1, 1, 1, 2, 2, 2",
      "evidence": [
        {
          "source": "finite-groupnames-q-16",
          "locator": "Character table: identity column and real/complex/symplectic annotations"
        },
        {
          "source": "gap",
          "locator": "Irr and section 71.12-5 Indicator"
        }
      ],
      "assumptions": [
        "Characteristic zero",
        "Finite-dimensional irreducibles over C",
        "Dimensions listed with multiplicity"
      ],
      "reviewStatus": "pending-expert-review",
      "revision": "2026.11-workbench.4"
    },
    {
      "id": "group:q-16#smallgroups-id",
      "subject": "group:q-16",
      "key": "smallgroups-id",
      "label": "GAP SmallGroups ID",
      "value": "SmallGroup(16,9)",
      "evidence": [
        {
          "source": "finite-groupnames-q-16",
          "locator": "Aliases; GAP/Magma code by ID"
        }
      ],
      "assumptions": [],
      "reviewStatus": "pending-expert-review",
      "revision": "2026.11-workbench.4"
    },
    {
      "id": "group:q-16#representations-1",
      "subject": "group:q-16",
      "key": "representations-1",
      "label": "Representation scope",
      "value": "The complete list of ordinary complex irrep dimensions is given above. Labels ρ1, ρ2, … follow the cited GroupNames character-table row order; they are local labels, not dimension-based identities.",
      "evidence": [
        {
          "source": "finite-groupnames-q-16",
          "locator": "Character table"
        }
      ],
      "assumptions": [],
      "reviewStatus": "pending-expert-review",
      "revision": "2026.11-workbench.4"
    },
    {
      "id": "group:q-16#representations-2",
      "subject": "group:q-16",
      "key": "representations-2",
      "label": "Representation scope",
      "value": "Real, Complex and Quaternionic refer to Frobenius–Schur type (+1, 0, −1). The linked character table provides additional data; this entry does not supply matrices or a modular representation catalogue.",
      "evidence": [
        {
          "source": "finite-groupnames-q-16",
          "locator": "Character table: identity column and real/complex/symplectic annotations"
        },
        {
          "source": "gap",
          "locator": "Irr and section 71.12-5 Indicator"
        }
      ],
      "assumptions": [],
      "reviewStatus": "pending-expert-review",
      "revision": "2026.11-workbench.4"
    },
    {
      "id": "group:q-16#relation-1",
      "subject": "group:q-16",
      "key": "relation-1",
      "label": "Family",
      "value": "family:finite-dicyclic",
      "evidence": [
        {
          "source": "finite-groupnames-q-16",
          "locator": "Heading; Aliases"
        }
      ],
      "assumptions": [],
      "relationship": "member-of",
      "reviewStatus": "pending-expert-review",
      "revision": "2026.11-workbench.4"
    },
    {
      "id": "group:q-16#relation-2",
      "subject": "group:q-16",
      "key": "relation-2",
      "label": "Q₁₆ / C₂ ≅ D₈",
      "value": "group:d-8",
      "evidence": [
        {
          "source": "finite-groupnames-q-16",
          "locator": "Centre: quotient D₄ in the order-eight convention"
        }
      ],
      "assumptions": [],
      "relationship": "central-quotient",
      "reviewStatus": "pending-expert-review",
      "revision": "2026.11-workbench.4"
    }
  ],
  "sources": [
    {
      "id": "gap",
      "title": "GAP · Characters and symmetrizations",
      "authors": [],
      "url": "https://gap-system.github.io/gap/doc/ref/chap72_mj.html",
      "kind": "documentation",
      "locatorHint": "Sections 72.7–72.8 and 72.11: scalar products, decompositions, symmetric and exterior powers",
      "licenseNote": "Linked source with original summaries of mathematical facts. Consult the source for its own terms; no blanket redistribution license is asserted."
    },
    {
      "id": "finite-groupnames-q-16",
      "title": "GroupNames: Q₁₆",
      "authors": [
        "Tim Dokchitser"
      ],
      "url": "https://people.maths.bris.ac.uk/~matyd/GroupNames/1/Q16.html",
      "kind": "database",
      "locatorHint": "Order, Centre, Aliases, generators and relations, Character table",
      "licenseNote": "Linked for verification. No redistribution licence is asserted; this dataset contains original summaries and selected mathematical facts, not source tables."
    }
  ],
  "review": {
    "status": "pending-expert-review",
    "label": "Expert review pending",
    "currentReviews": 0,
    "staleReviews": 0,
    "fingerprint": "665025a55e1d515d157f6062a0d262b7a9ccb5b5f493f65fa45afc45051529b9",
    "reviewers": []
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}