Reserved Notation "a ~~ b" (at level 54).
Reserved Notation "a ~> b" (at level 70, right associativity).
Reserved Notation "a ≃ b" (at level 70, right associativity).
Reserved Notation "a ~~ b" (at level 54).
Reserved Notation "a ~> b" (at level 70, right associativity).
Reserved Notation "a ≃ b" (at level 70, right associativity).