fact: Definition is_bigTheta {W} (F : set_system T) (g : T -> W) := [qualify f : T -> V | `[< bigTheta_def F f g >] ].
imports: HB(structures) mathcomp(all_ssreflect ssralg ssrnum) mathcomp(mathcomp_extra boolp classical_sets functions) ereal reals signed topology normedtype prodnormedzmodule