fact: Fixpoint rotations t := if t is BinNode l r then let rec := [seq BinNode lrot r | lrot <- rotations l] ++ [seq BinNode l rrot | rrot <- rotations r] in if l is BinNode ll lr then BinNode ll (BinNode lr r) :: rec else rec else [::].
imports: HB(structures) mathcomp(all_ssreflect) tools combclass ordtype