proposition: Lemma diskF_rot : diskF (rot n0 r) =i diskF r.
proof: Proof. by move=> x; rewrite inE /= fband_rot diskN_rot. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype path fingraph) fourcolor(hypermap jordan color geometry patch)