Depreciation
Kt=yt+y _t-I(I-?)+y_t-2(I-?)²+....
?K_t = y _t-?K_t
?K_t=y_t
K_t    K_t    -?
This depreciation is more realistic than
a concept based on ??
argument need not impair my formula
formulation in terms of whole of a part,
see above: in marginal terms