[MarkusQ]

This isn't quite what's going on. A better reading might be "which is a";

"Ǝx s.t. x∈ℕ" (there exists an x such that x is in the naturals) is just being shortened to "Ǝx∋ℕ" (there exists an x in the naturals), or there exists an x which is in the naturals.

It's not really that different from the normal usage.

[drdeca]

If that’s it, why is it using ∋ rather than ∈? I would expect “Ǝx∈ℕ”.

[MarkusQ]

Oh, doh! I'd missed that.

Yeah, that's...an unusual choice.

[pwdisswordfishq]

> Ǝx∋ℕ

"There is an x such that the set of natural numbers is a member of x"?

[MarkusQ]

Yeah, my bad. My eyes autocorrected it.