Interactive Learning Platform

Learn Lean 4 Theorem Proving

Master mathematical proof writing with an interactive editor and real-time compilation. Start proving theorems in your browser right now!

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Structured Learning

Problem Sets

Follow a guided path with curated problem sets covering Lean fundamentals, functions, logic, and more. Perfect for systematic learning!

What's included:

  • • 15+ problems from basics to advanced
  • • Step-by-step hints and explanations
  • • Instant feedback with Lean compiler
  • • Track your learning progress

Free Exploration

Interactive Editor

Jump straight into the interactive editor to experiment freely. Load examples, write proofs, and get immediate feedback.

What you can do:

  • • Write and compile Lean code instantly
  • • Load pre-built examples
  • • Experiment with theorems
  • • Learn at your own pace

Lean 4 Proof Assistant

Write and verify mathematical proofs interactively

Checking status...

Code Editor

Output

Output will appear here after compilation...

Examples

Click an example to load it into the editor

💡 Tips for Learning Lean

  • Use rfl (reflexivity) to prove things that are definitionally equal
  • The #check command shows the type of an expression
  • The #eval command evaluates an expression and shows the result
  • Start with simple examples and gradually work up to more complex proofs
  • Read error messages carefully - they often tell you exactly what's wrong

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CreatorCubi Platform

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What you can do:

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  • • Deploy to your custom domain
  • • Manage all your Cubicubes
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Your Cubicube

This Site

Use the "Log in" button in the header navigation above to sign in to YOUR Cubicube. This is for accessing your personal site's features and content.

What you can do:

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Learning Resources

Expand your Lean knowledge with these helpful resources

📚 Official Docs

Read the official Lean 4 documentation and learn from comprehensive guides.

Visit Lean Docs →

🎓 Theorem Proving

Learn theorem proving in Lean 4 with interactive tutorials and exercises.

Start Learning →

💡 Community

Join the Lean community on Zulip to ask questions and share insights.

Join Discussion →

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