How can I find MAX with relational algebra?

Question

Working with databases, how can I find MAX using relational algebra?

Answer 1

I've forgotten most of the relational algebra syntax now. A query just using SELECT, PROJECT, MINUS and RENAME would be

SELECT v1.number
FROM values v1
MINUS
SELECT v1.number
FROM values v1 JOIN values v2 ON v2.number > v1.number

Hopefully you can translate!