The relational algebra and functional dependencies are different. The relational algebra is a number of operations that together provide a theoretical foundatio

The relational algebra and functional dependencies are different. The relational algebra is a number of operations that together provide a theoretical foundation to relational databases, whilst functional dependencies describe how data depends on other data. They're not in any sense the same term. Strictly speaking, you're only talking about the relational algebra if you're talking about what the page you mentioned is talking about. Schema refinement is also a known term; normalisation refers to refining a schema into a normal form; it is possible to refine a schema without deliberately reducing it to such a thing (although if you've produced a database that's not in 1NF, kudos!). Like you, I'm surprised that it's not mentioned, although I'm also not convinced that it needs to be mentioned. Normal forms just refer to what redundancies are avoided, and in practice all you care about is whether the redundancy is hindering you. Blindly normalising is a great cargo-cultish way to end up with an underperforming database.