proof_by_contraposition
CommunityMaster contraposition proofs in Lean.
Authorbneb
Version1.0.0
Installs0
System Documentation
What problem does it solve?
Contraposition-based proofs in Lean 4: convert implications to their contrapositive to obtain a more concrete hypothesis and complete the proof.
Core Features & Use Cases
- Convert P → Q into ¬Q → ¬P and apply standard Lean 4 tactics (contrapose/contrapose!, push_neg) to discharge goals.
- Works well when the negation of the conclusion yields a stronger or more usable assumption, such as in inequalities, divisibility, or connectivity arguments.
- Provides a Lean 4 template and worked example showing a typical contrapositive proof flow.
Quick Start
Apply contraposition in Lean 4 to convert P → Q into ¬Q → ¬P and complete the proof from the negated premise.
Dependency Matrix
Required Modules
None requiredComponents
Standard package💻 Claude Code Installation
Recommended: Let Claude install automatically. Simply copy and paste the text below to Claude Code.
Please help me install this Skill: Name: proof_by_contraposition Download link: https://github.com/bneb/perqed/archive/main.zip#proof-by-contraposition Please download this .zip file, extract it, and install it in the .claude/skills/ directory.
Agent Skills Search Helper
Install a tiny helper to your Agent, search and equip skill from 471,000+ vetted skills library on demand.