Reserved Notation "a '⊢ᴄᴏ' b : c ∼ d" (at level 20, b at level 99).
Reserved Notation "Γ '+' x : c" (at level 50, x at level 99).
Reserved Notation "Γ '++' x : a ∼ b" (at level 50, x at level 99).
Reserved Notation "a '⊢ᴄᴏ' b : c ∼ d" (at level 20, b at level 99).
Reserved Notation "Γ '+' x : c" (at level 50, x at level 99).
Reserved Notation "Γ '++' x : a ∼ b" (at level 50, x at level 99).