Interesting, my experience in classes using set theory was the opposite, where ∋ only meant “such that” and ∈ only meant “is a member of”.

Learning programming syntax at the same time made it frustrating to learn that math symbols were less strictly defined and less universal, that it was best to write proofs/derivations/etc in plain English in many cases instead of the neat symbols

as a math major i had the same confusion; for such that i use "s.t.". but apparently peano used ∋ to mean such that:

https://math.stackexchange.com/questions/15455/backwards-eps...

It also doesn't make much sense

> There exists a raven such that the vector of hours.

The vector of hours what?