About Loogle searches Lean and Mathlib definitions and theorems. You can use Loogle from within the Lean4 VSCode language extension using (by default) Ctrl-K Ctrl-S. You can also try the #loogle command from LeanSearchClient, the CLI version, the Loogle VS Code extension, the lean.nvim integration or the Zulip bot. Usage Loogle finds definitions and lemmas in various ways: By constant: 🔍 Real.sin