Metamath

Metamath is a formal system and a proof assistant that is used to develop and verify mathematical theorems in a rigorous way. It provides a framework for expressing mathematical statements and their proofs in a purely logical and syntactical format. Key features of Metamath include: 1. **Formal Language**: Metamath uses a simple symbolic language to express mathematical definitions, theorems, and proofs. This language is designed to be simple yet powerful enough to capture the nuances of mathematics.