Lean is an interactive theorem prover and dependently typed functional programming language originally developed by Leonardo de Moura at Microsoft Research beginning in 2013, designed to combine formal mathematical proof verification with a modern, fast, and extensible functional programming language usable for general software development. Lean's later major version, Lean 4, is notable for being substantially self-hosted, with much of its own compiler and tooling written in Lean itself, and the language has been adopted by a large mathematical community for the Mathlib project, an extensive, community-built formalized mathematics library.
Facts
Classification
Typing Discipline Typing Discipline First Released SignificanceAwarded the 2025 ACM SIGPLAN Programming Languages Software Award. 1 Connections
Associated With
Sibling interactive proof assistants.
Follows Typing Discipline
Entity-backed identity for the typing discipline value this language already carries as an enum fact, resolved to a concept entity by an explicit value-to-entity map (phase 3 bucket conversion, docs\design_entity_backed_browse_buckets_20260928.md). The enum fact itself stays on the entity unchanged.
Entity-backed identity for the typing discipline value this language already carries as an enum fact, resolved to a concept entity by an explicit value-to-entity map (phase 3 bucket conversion, docs\design_entity_backed_browse_buckets_20260928.md). The enum fact itself stays on the entity unchanged.
In Field
Source Lean (proof assistant) - Wikipedia
Licensed Under
Entity-backed identity for the license enum value this item already carries, resolved to a software license concept by an explicit value-to-entity map (phase 3 bucket conversion, docs\design_entity_backed_browse_buckets_20260928.md). The license fact itself stays on the item unchanged.
Sources
1. Lean (proof assistant) - Wikipedia
History, 2025 paragraph
In 2025, ACM SIGPLAN Programming Languages Software Award was awarded to Gabriel Ebner, Soonho Kong, Leo de Moura and Sebastian Ullrich for Lean
Infobox typing field
typing = static, strong, inferred
In Field: Programming Language Theory, Lead sentence
Lean is a proof assistant and a functional programming language.
View the Source2. Wikidata: Lean
- Wikidata Q6509476, resolved via en.wikipedia pageprops (wave rule R-L)
- Wikidata Q6509476 P275 (license)
View the SourceDependent type (Wikipedia)
In Group: Dependently Typed Proof Assistant Languages, article names Lean among functional languages using dependent types to help reduce bugsView the Source Reader Challenges (0)
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