The universal cover of the real projective line

Jack Morava

Published 2023-11-11Version 1

We construct an interesting topological cover of the multiplicative group of the real line, related to Tate's elliptic curve with $q = e^\pi$. We use the language of homological algebra, 2D Lorentz geometry and high-school trigonometry; the intent is expository but the suggested applications may be unusual.