They didn't actually determine it. The cheated by giving it a single letter variable name, and ran with it. It's the mathematical equivalent of buying using a rubber check that is never cashed, so everything is OK.
Isn't I a glyph in the same way that 1 is a glyph?
Yes, checks are money. But they still feel different from cash.
well, because they are not technically money because the check could be bad; you have no way to verify if it would bounce.
I mean, you can have faith in whatever you want, but if you read to the end of the article the mathematicians themselves are the ones saying the conditions seem more to agree with the scenario where they won't.