binrel_binop.lean:1:8-1:11: warning: declaration uses `sorry`
ex1 (a : Int) (b c : Nat) : a = ↑b - ↑c
binrel_binop.lean:5:8-5:11: warning: declaration uses `sorry`
ex2 (a : Int) (b c : Nat) : a = ↑b - ↑c
binrel_binop.lean:9:8-9:11: warning: declaration uses `sorry`
ex3 (a : Int) (b c : Nat) : a = ↑(b - c)