I did mean "near-instinctive" to apply after having learned about the concepts of surjective, injective and bijective functions. These are so basic and importan

I did mean "near-instinctive" to apply after having learned about the concepts of surjective, injective and bijective functions. These are so basic and important that I believe you can't be a professional programmer without having been exposed to them, and having them stick at an instinctive level.