> or just assume since the case is simple That's like what the blog post is about where you're tagging values you assume have a certain property. > I suspect

> or just assume since the case is simple That's like what the blog post is about where you're tagging values you assume have a certain property. > I suspect that if we factor out such basics, the amount of proof for a reasonable function may become manageable. It's not obvious how you contain the complexity though and you don't need a lot before it becomes well beyond practical for even experienced programmers. The moment you have to write an algebraic proof where variables are multiplied together you're in the realm of nonlinear arithmetic which is undecidable for example, and writing proofs is hard. Mainstream languages contain the proof complexity by limiting what you can express e.g. it's trivial for the computer to prove "String = String" and "Dictionary = HashTable" as part of type checking.