A "mixed economy" has two poles with a purely competitive market like that envisioned by Adam Smith at one end and a single seller operation like the Post Office at the other. In between you find oligopolistic concerns like Microsoft or Google that dominate their respective niches because of their size and political clout. Additionally, socialism and communism differ fundamentally in that one argues from each according to his abilities to each according to his work, versus from each according to her abilities to each according to her needs. You have every right to your own opinions, but not to your own facts.A "mixed economy" is another way of saying "capitalism." For all practical purposes, "socialism" and "communism are the same exact thing. There are no others.