But the cool part is that the YC is not actually a primitive. Primitives in lambda calculus are essentially just variables, function definition, and application

But the cool part is that the YC is not actually a primitive. Primitives in lambda calculus are essentially just variables, function definition, and application. At a first glance, you wouldn't tell that you could express infinite computation from such rudimentary tools, but the YC shows that you actually can.