Theorien über den Mehrwert
While Marx used the concept of the law of value in his works "Grundrisse", "A Contribution to the Critique of Political Economy", "Theories of Surplus Value" and "Das Kapital", he did not explicitly formalise its full meaning in a mathematical sense, and therefore how it should be exactly defined remains to some extent a controversial topic in Marxian economics. Different economists dispute how the proportionality between exchange-value and labour-time should be mathematically understood or modeled, and about the measures which are relevant.