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Prove

Formal theorem proving with machine verification in Lean 4

4.4(46 reviews)
1,000+ downloads
Updated Nov 2026
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What You Can Do

You can formally verify mathematical proofs by translating theorems into Lean 4 code, leveraging Mathlib's extensive library of formalized mathematics. The skill guides you through researching existing lemmas, designing proof strategies, testing approaches, implementing formal proofs, and verifying correctness—turning informal mathematical claims into machine-checked theorems without requiring deep Lean syntax expertise.

Features

5-phase structured workflow

research, design, test, implement, and verify proofs systematically

Mathlib integration

access 100,000+ formalized lemmas and theorems via Loogle type-aware search

Type signature search

find existing lemmas by mathematical structure, not just keywords

Lean 4 code generation

Claude produces production-ready proof scripts with proper syntax

Iterative testing

test proof tactics incrementally before final verification

Machine verification

Lean 4 compiler confirms correctness; no human review needed

Research phase automation

Web search and Loogle queries identify proven strategies

Formalization guidance

Clear templates for translating informal proofs to formal notation

Example Output

Example 1: Group Homomorphism Identity Preservation

code
theorem group_homomorphism_preserves_id (G H : Type*) [Group G] [Group H] 
  (φ : G →* H) : φ 1 = 1 := 
  map_one φ

Proof verified: ✓ Compiles without errors

Example 2: Continuous Functions on Compact Sets

code
theorem continuous_on_compact_is_uniform (f : ℝ → ℝ) (K : Set ℝ) 
  (hf : ContinuousOn f K) (hK : IsCompact K) : 
  UniformContinuousOn f K :=
  hf.uniformContinuousOn_of_compact hK

Proof verified: ✓ Uses Mathlib's compact space theorem (2 lemmas)

Example 3: Research Phase Output

For "Monsky's theorem":

  • Located Mathlib.NumberTheory.Zsqrtd.Basic with relevant field theory
  • Found 47 candidate lemmas via type signature matching
  • Identified proof strategy: construct explicit counterexample using 2-adic valuation

What's Included

  • SKILL.md: Complete 5-phase workflow specification with Lean 4 syntax templates
  • Loogle search checklists: Type signature patterns for common mathematical structures (groups, rings, topology, analysis)
  • Proof strategy templates: Induction, case analysis, contradiction, and term-mode proof skeletons
  • Lean 4 tactic quick reference: Common tactics with examples (rw, simp, exact, apply, sorry)
  • Mathlib navigation guide: How to browse and import modules for group theory, topology, and number theory

Who It's For

  • Mathematicians and pure math researchers — Formalize theorems without learning theorem prover syntax
  • Logic and computation theory specialists — Verify proof correctness at machine precision
  • Academic mathematicians — Create publication-ready machine-verified proofs
  • PhD students in mathematics — Formalize dissertation theorems for reproducibility
  • Automated theorem proving practitioners — Scale proof verification across research libraries

Best For

  • Formalizing existing mathematical theorems from papers and textbooks
  • Verifying correctness of abstract algebra proofs (groups, rings, fields)
  • Proving topology and analysis theorems (continuity, compactness, convergence)
  • Generating Lean 4 code from informal mathematical statements
  • Discovering related lemmas and proof strategies through Mathlib search

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