Lean

Lean is an open-source interactive theorem prover and programming language. It is designed for formal verification of mathematical theorems and software, allowing users to write precise mathematical statements and prove them rigorously using a combination of automated and interactive proof techniques.

This tool is primarily for mathematicians, logicians, and computer scientists who are involved in formal methods, proof-checking, and developing verified software. It is used in academic research and education for teaching logic and formal reasoning, as well as in industry for ensuring the correctness of critical systems.