Yeah, I assumed. No way 86 pages are needed for a proof of ‘1+1=2’.

That being said, it’d be nice for there to actually be a “proof” of 1+1=2, made as concise and simple as possible, while retaining all the precision required of such proof, including a complete set of axioms.

This, obviously isn’t is, nor does it try to. It’s not the “1+1=2” book, ot’s the theoretical fpindations of matheđatics book. Nothing wrong with that.

What’s missing here os the definition that we’re working in base 10. While it won’t be a proof, Fibbonaci has his nice little Liber Abbaci where he explains arabic numerals. A system of axioms for base 10, a definition of addition and your succession function would suffice. Probably what the originals were going for, but I can’t imagine how that would take 86 pages. Reading it’s been on my todo list, but I doubt I’ll manage 86 pages of modern math designed to be harder to read than egyptian hieroglyphs.

It’s not wrong. The “common center” lies inside the Sun.

Therefore, the Sun orbits itself and the Earth orbits the Sun.

And no such century lasted for a century either.