 (Here, and in what follows, the notation \(V(\bi,\bj)\) indicates the payoff to strategy \(\bi\) when \(\bi\) plays \(\bj\).) MS says that any invaders do strictly worse against the natives than the natives themselves do against the natives or else they get exactly the same payoff against the natives as the natives themselves do, but the native does better against the invader than the invader himself does.