Are the following sentences correct, especially what is in bold?
-- 1. Your car is faster than Ana's car.
Tu carro es más rápido que el de Ana.
-- 2. Your blouse is redder than Ana's blouse.
Tu blusa es más roja que la de Ana.
-- 3. Your cars are faster than Ana's cars.
Tus carros son más rápidos que los de Ana.
-- 4. Your blouse is redder than Ana's blouse.
Tus blusas son más rojas que las de Ana.
What is the grammar structure in bold called? I don't think they are relative pronouns or are they?