Not that I got very deep into mathematics but higher level math is all formal logic and proofs. There are mathematical theorems that are proven to be true/closed for many years by mathematicians before they find commercial/practical applications.

For the HN audience, much of the power and usefulness of RDBMSs is derived from the relational model and the relational algebra it sits on [1].

[1] https://en.wikipedia.org/wiki/Relational_algebra