proposition: Lemma diskFC_rot : diskFC (rot n0 r) =i diskFC 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)