#check (take a : nat, have H : 0, from rfl a, (H a a) : ∀ a : nat, a = a) #check (take a : nat, have H : a = a, from rfl a, (H a a) : ∀ a : nat, a = a) #check (take a : nat, have H : a = a, from a + 0, (H a a) : ∀ a : nat, a = a) #check (take a : nat, have H : a = a, from rfl, (H a) : ∀ a : nat, a = a) #check (take a : nat, have H : a = a, from rfl, H : ∀ a : nat, a = a)