2 problems

For rational magnetic flux $p/q$, let $r$ denote the gap label and let $\sigma_{\rm H}$ be the Chern number associated with the gap, satisfying the Diophantine equation … for some…

Generic sign-ambiguity conjecture. For generic Hofstadter models, the mod $q$ ambiguity in the solution of the Diophantine equation is a sign ambiguity: the Chern number is either…