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sub:assertion {
  sub:mathlib-formalization a schema:SoftwareSourceCode;
    dct:description "Machine-verified Lean 4 formalization of the Pythagorean theorem in Mathlib, stated in if-and-only-if angle-at-point form: dist p₁ p₃ * dist p₁ p₃ = dist p₁ p₂ * dist p₁ p₂ + dist p₃ p₂ * dist p₃ p₂ ↔ angle p₁ p₂ p₃ = π/2. Proved for points of a metric space that is a torsor over a real inner product space (Euclidean affine space)."@en;
    dct:isPartOf <https://github.com/leanprover-community/mathlib4>;
    dct:subject wd:Q11518;
    rdfs:label "EuclideanGeometry.dist_sq_eq_dist_sq_add_dist_sq_iff_angle_eq_pi_div_two";
    rdfs:seeAlso <https://leanprover-community.github.io/mathlib4_docs/Mathlib/Geometry/Euclidean/Angle/Unoriented/RightAngle.html#EuclideanGeometry.dist_sq_eq_dist_sq_add_dist_sq_iff_angle_eq_pi_div_two>;
    skos:related wd:Q162886, wd:Q214159;
    schema:programmingLanguage "Lean 4" .
}

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    prov:wasDerivedFrom <https://github.com/leanprover-community/mathlib4>, <https://leanprover-community.github.io/mathlib4_docs/Mathlib/Geometry/Euclidean/Angle/Unoriented/RightAngle.html> .
}

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    dct:created "2026-07-08T17:44:04Z"^^xsd:dateTime;
    dct:creator orcid:0000-0002-8042-4131;
    dct:license <https://creativecommons.org/licenses/by/4.0/>;
    rdfs:label "Lean 4 Mathlib formalization of the Pythagorean theorem" .
  
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    dct:description "AI assistant by Anthropic that drafted this nanopublication."@en;
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