Given a function F that accepts an argument x and returns y, its inverse is another function which, when passed y will return x. For dyadic functions, the ince

Given a function F that accepts an argument x and returns y, its inverse is another function which, when passed y will return x. For dyadic functions, the incerse argument is always the right side one. So negation is its own inverse. So the inverse of 2+ is indeed subtraction of 2.