{
  "schema_version": 1,
  "id": "evt-2017-mathlib3",
  "slug": "mathlib3-formal-mathematics-library",
  "title": {
    "en": "Mathlib3 creates a shared Lean library for collaborative formal mathematics",
    "zh-CN": "Mathlib3 建立面向协作式形式数学的共享 Lean 数学库"
  },
  "dates": {
    "event": "2017-07-21",
    "first_public_claim": null,
    "paper_release": null,
    "artifact_release": "2017-07-21",
    "independently_verified": null,
    "added_to_chronicle": "2026-09-15",
    "last_updated": "2026-09-27"
  },
  "event_types": [
    "formalization",
    "infrastructure"
  ],
  "significance": {
    "tier": "H2",
    "rationale": {
      "en": "Mathlib transformed Lean from a proof-assistant platform into a growing shared corpus of reusable formal mathematics. The library's scale, collaborative development model and machine-readable theorem/proof data later made it central infrastructure for Lean-based AI theorem proving and benchmark construction.",
      "zh-CN": "Mathlib 把 Lean 从证明助手平台进一步发展为持续增长、可复用的共享形式数学语料库；其规模、协作开发模式以及机器可读的定理与证明数据，后来使其成为基于 Lean 的 AI 定理证明和基准构建的核心基础设施。"
    }
  },
  "mathematical_novelty": {
    "type": "tooling_only"
  },
  "interfaces": [
    "formal",
    "symbolic"
  ],
  "claim": {
    "en": "The preserved leanprover-community/mathlib3 repository was created on GitHub on 21 July 2017, providing the exact artifact anchor used for this Event. The later mathlib community paper documents the project as a community-driven effort to build a unified library of mathematics formalized in Lean and explains its mathematical, automation and organizational architecture.",
    "zh-CN": "保留至今的 leanprover-community/mathlib3 GitHub 仓库创建于 2017 年 7 月 21 日，因此本 Event 以该精确 artifact 时间作为 canonical 锚点。后来由 mathlib 社群发表的论文将该项目描述为在 Lean 中构建统一形式数学库的社区协作工程，并系统说明其数学结构、自动化与组织架构。"
  },
  "summary": {
    "en": "Mathlib organized community-authored Lean definitions, theorems, proofs and tactics into a common mathematical library spanning algebra, analysis, topology, number theory and other areas. Shared APIs and review practices made formal developments composable rather than isolated project artifacts.",
    "zh-CN": "Mathlib 将社群编写的 Lean 定义、定理、证明与 tactics 组织为共享数学库，逐步覆盖代数、分析、拓扑、数论等领域；统一 API 与协作审查实践使形式化成果能够相互复用，而非停留在彼此隔离的项目中。"
  },
  "why_it_matters": {
    "en": "Modern learning-based theorem provers need not only a proof checker but also large libraries of formal statements, proof states and dependencies. Mathlib became precisely that substrate for Lean, later underpinning environments and datasets such as LeanDojo and a wide range of LLM-based formal-math systems.",
    "zh-CN": "现代学习式定理证明不仅需要证明检查器，也需要大规模形式陈述、证明状态与依赖关系语料。Mathlib 正是 Lean 生态中的这一基础层，后来直接支撑 LeanDojo 等环境、数据集以及大量基于 LLM 的形式数学系统。"
  },
  "ai_role": {
    "level": "computation_only",
    "description": {
      "en": "The mathematical library was primarily authored and reviewed by humans, while Lean mechanically checked the formal content; the Event concerns creation of machine-readable proof infrastructure rather than autonomous AI discovery.",
      "zh-CN": "数学库内容主要由人类编写与审查，Lean 负责机械检查；本 Event 记录的是机器可读证明基础设施的形成，而非自主 AI 数学发现。"
    }
  },
  "human_contribution": {
    "description": {
      "en": "The Lean mathematical community collaboratively developed, reviewed and maintained reusable formal definitions, theorems, proofs and automation in a shared repository.",
      "zh-CN": "Lean 数学社群以协作方式在共享仓库中开发、审查并维护可复用的形式定义、定理、证明与自动化工具。"
    }
  },
  "systems": [
    "lean",
    "mathlib3"
  ],
  "organizations": [
    "leanprover-community"
  ],
  "people": [],
  "problems": [
    "formal-mathematical-knowledge"
  ],
  "methods": [
    "mathematical-library",
    "collaborative-formalization",
    "proof-checking",
    "interactive-theorem-proving"
  ],
  "verification": {
    "evidence_level": "E3",
    "status": "claimed",
    "formal_assurance": "artifact_available",
    "history": [
      {
        "date": "2017-07-21",
        "status": "claimed",
        "evidence_level": "E3",
        "note": {
          "en": "The preserved public repository provides an exact GitHub creation timestamp and directly inspectable formal artifact; the later mathlib paper documents the library's community-driven architecture and scope.",
          "zh-CN": "保留的公开仓库提供精确 GitHub 创建时间戳以及可直接检查的形式化 artifact；后来的 mathlib 论文记录了该数学库的社区协作架构与覆盖范围。"
        }
      }
    ]
  },
  "sources": [
    {
      "id": "github-mathlib3-repository",
      "tier": "S1",
      "type": "repository",
      "title": "leanprover-community/mathlib3 repository",
      "url": "https://github.com/leanprover-community/mathlib3",
      "primary": true,
      "published_date": null,
      "accessed_at": "2026-09-15"
    },
    {
      "id": "arxiv-lean-mathematical-library-2019",
      "tier": "S1",
      "type": "paper",
      "title": "The Lean mathematical library",
      "url": "https://arxiv.org/abs/1910.09336",
      "primary": false,
      "published_date": "2019-10-21",
      "accessed_at": "2026-09-15"
    }
  ],
  "artifacts": [
    {
      "id": "mathlib3-repository",
      "kind": "code",
      "title": "Lean 3 mathlib repository",
      "url": "https://github.com/leanprover-community/mathlib3"
    }
  ],
  "relationships": {
    "predecessors": [
      "evt-2015-lean"
    ],
    "successors": [
      "evt-2023-leandojo",
      "evt-2026-lean-pool"
    ],
    "related": []
  },
  "timeline": {
    "featured": true,
    "significance": "primary"
  },
  "tags": [
    "lean",
    "mathlib",
    "formal-mathematics",
    "mathematical-library",
    "proof-assistant",
    "open-source"
  ],
  "editorial": {
    "created_at": "2026-09-15",
    "last_reviewed": "2026-09-27",
    "reviewers": [
      "Charlie-Wang-03"
    ]
  },
  "corrections": []
}