This way, we obtain the power spectrum of the unmodulated laser signal shifted to the

zero frequency as

0] are the complex viscosity and

zero frequency viscosity, respectively.

Therefore, the root at the long run or

zero frequency appears as a component of the seasonal polynomial in (1).

On this basis the hypothesis of one unit root at the

zero frequency and one at the biannual frequency is not rejected.

When the frequency grouping around the fundamentals expands downward beyond

zero frequency, the spectrum "folds back" as though reflected from

zero frequency.

This can be accomplished by shifting the

zero frequency point of the Doppler up or down by the above stated amount.

For example, if p and m are both I(1,1), they may be cointegrated: at the long-run or

zero frequency if u is I(0,1), at the seasonal frequency if u is I(1,0), or at both the long-run and zero frequencies if u is I(0,0).

Despite these differences, the findings reported in this paper indicate that capital indeed is a far more important factor than labor in the determination of output at the

zero frequency band.

It is worth mentioning that the dynamic stiffness approach identified the

zero frequency.

Qualitatively, this appears to be consistent with our optimum values which were obtained at

zero frequency limit.

Note that a VNA cannot measure down to zero signal frequency, so a careful procedure must he followed to interpolate the

zero frequency response between the lower and upper sidebands.