What's the difference between "function" and "relation" in logic? What's the difference between "function" and "relation" in logic?
Why do we cosider them apart?
I think every relation expresses a function...

A function takes terms as arguments, and results in another term, denoting an object.
A relation takes terms as arguments, and results in a sentence, denoting a claim
As such, a relation (i.e claim) can be said to hold true or not, but it makes no sense to say "this function (i.e object) holds true (or false)"
