subtraction

The passage around this formula

The two numbers are worth writing down side by side, because the difference between them is itself a historical fact rather than a rounding error. If $N_0$ is the component count at a reference time $t_0$ , the extrapolation in each case took the form $N(t) \approx N_0 \cdot 2^{(t - t_0)/T}$. with T $\approx$ 1 year in the 1965 paper’s implied rate and T $\approx$ 2 years in Moore’s own 1975 revision [ 1 , 2 ] . A model that halves its own rate parameter after a decade of data is not a law of nature; it is a working forecast that its author corrected in public once, using new evidence, at a named conference. That the popular shorthand later collapsed both versions into a single unchanging “law” says more about the…

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