A semivariogram does not determine stationarity
= A semivariogram does not determine stationarity
If $W(s)$ is stationary, then $Z(s)=W(s)-W(0)$ has exactly the same increments and <semivariogram>, but $\operatorname{Var}Z(s)=2\gamma_W(s)$ is generally nonconstant. Thus existence of a stationary <covariance> model for a <semivariogram> does not imply stationarity of every process with that <semivariogram>. Adding an independent random constant also leaves the <semivariogram> unchanged while changing the <covariogram>.