α : Type u_2
β : Type u_1
γ : Type ?u.441085
δ : Type ?u.441088
r : α → β → Prop
p : γ → δ → Prop
b : Multiset β
⊢ (0 = 0 ∧ b = 0 ∨
      Exists fun {a} =>
        Exists fun {b_1} =>
          Exists fun {as} => Exists fun {bs} => r a b_1 ∧ Rel r as bs ∧ 0 = a ::ₘ as ∧ b = b_1 ::ₘ bs) ↔
    b = 0
α : Type u_2
β : Type u_1
γ : Type ?u.441085
δ : Type ?u.441088
r : α → β → Prop
p : γ → δ → Prop
b : Multiset β
⊢ Rel r 0 b ↔ b = 0
rw [Rel_iff]
no goals
α : Type u_2
β : Type u_1
γ : Type ?u.441085
δ : Type ?u.441088
r : α → β → Prop
p : γ → δ → Prop
b : Multiset β
⊢ (0 = 0 ∧ b = 0 ∨
      Exists fun {a} =>
        Exists fun {b_1} =>
          Exists fun {as} => Exists fun {bs} => r a b_1 ∧ Rel r as bs ∧ 0 = a ::ₘ as ∧ b = b_1 ::ₘ bs) ↔
    b = 0
simp