The end result of type checking a function body, so we're going to take that function name, called X0 here on the slide, and we're going to add it to the static environment, with the type, takes arguments T1, T2, T3 up to Tn, and returns a T. When you see the function syntax here with T1 star, separated arguments by star, and then an arrow for the T. If the function binding type checks appropriately. 