Hierarchy formed by avoidance: two connected nodes CANNOT be on the same level. Akin to electron shells. Superimposed is only possible if they are separated by other nodes.
- SET THEORY
- – TYPE THEORY
- – – MATHEMATICS
- – – NATURAL DEDUCTION
- – – – SET (mathematics)
- – – – PARAMETRIC POLYMORPHISM
- – – – FUNCTION (mathematics)
Mathematics and Natural Deduction are distinct and can be in the same shell.
Set, Parametric Polymorphism and Function (Mathematics) are distinct and can be in the same shell.
This means they do not link to each other directly on Wikipedia. Does it mean anything? I don’t know, but it might.