Most programmers spend years learning how to make software work.
Very few spend time learning how to make software provably correct.
That difference is exactly why systems like compilers, cryptography libraries, kernels, and formal mathematics increasingly rely on proof assistants such as Lean 4.
Lean 4 is not just another programming language. It sits at the intersection of programming, mathematics, theorem proving, and language design. And once you understand the core concepts, you begin to see software differently: not merely as instructions for machines, but as logical structures that can be verified.
So if you're starting with Lean 4, what are the most important things to actually learn?
