Marxian Economics and unfree markets

[Desperado]

Just a quick question. It's my understanding that Marx's LTV etc. are based on ideas of a (relatively) free market. So, in a form of monopoly capitalism (whether state or otherwise), it's irrelevant? That is, the exploitation would take on a more similar form to that of feudal or slave societies?

[Broletariat]

The LTV still holds, this is because the LTV is a definition. Given that labour is alienated, we define the social relationship between people exchanging commodities as value relationships. Price is not always equal to value, but total social price is always equal to total social value. If someone gets ripped off, they off less money to spend elsewhere basically.