epsilon_delta_bounding

What problem does it solve?

The epsilon-delta method formalizes the intuitive notion of "closeness" in analysis. To prove lim_{x→a} f(x) = L, one must exhibit δ(ε) > 0 such that 0 < |x - a| < δ → |f(x) - L| < ε. The same structure extends to sequences, uniform continuity, and convergence in metric spaces.

Core Features & Use Cases

• Construct explicit δ(ε) or N witnesses to certify limits, continuity, and convergence within Lean 4 / mathlib4.
• Leverage Lean tactics like norm_num, positivity, linarith, and gcongr to close arithmetic bounds automatically.
• Provide end-to-end templates and examples for common limit and continuity proofs in Lean 4.

Quick Start

Provide a Lean 4 goal for a limit or convergence and request an explicit δ(ε) witness to complete the proof.