Matt McIrvin on Nostr: I'm comfortable with saying "in the real number system (or the complex number ...

I'm comfortable with saying "in the real number system (or the complex number system), 0.9999... = 1". Maybe someone can formulate some extension with infinitesimals in which it makes sense to say it's not (though my impression is that such notation is not very useful in such systems). But the real numbers don't have infinitesimals.