I have this assignement that asks to say if the following statement is true or false, and possibly justifying the answer:
"Let L₁, L₂ be decidable languages.
For every language L s.t. L₁ ⊆ L ⊆ L₂, L is decidable too
My first idea was to use the Halting Problem Language as L and show that is not decidable to prove the statement is false.
I tried to ask the Professor and he confirmed me that the assignment is false but he gave me a hint about explicitly describing the two languages L₁ and L₂, but I don't know which one would fit for this scope.