I came accross a Marx's passage which could be interesting in
disussing Duncan's idea that
the gross product contains means of production of various
vintages, produced under different technical conditions, and
embodying labor of different vintages and different
productivities. Thus the labor embodied in the gross product
is under these circumstances a *vector* of labor of different
vintages. The definition of the MEL as the ratio of a scalar
(the contemporary value of the gross product at market prices)
to a vector (the labor embodied in the gross product) is
incoherent mathematically.
Recent developments..., p. 27
On the contrary, Marx says:
Thus the value of a commodity is equally determined by
the quantity of *materialised (past)* labour and by the
quantity of *living (immediate)* labour required for its
production. In other words: the quantities of labour are
in no way affected by the *formal difference* of whether
the labour is materialised or living, past or present
(immediate).
Theories, II, p. 399
Alejandro Ramos M.