Given two infinite sets X $X$ and I, $I$, and a filter {\cal F} ${\cal F}$ on I, $I$, one defines as usual the equivalence relation \approx_{\cal F} $\approx_{\cal F}$ on X^I $X^I$ and obtains the reduced power $Y = X^I / \approx_{\cal F}F}$.
Question 1 : to what extent do such reduced powers differ when one filter on I $I$ is changed to another filter on I $I$ ?
Question 2 : consider question 1 in the case of different ultrafilters on I, $I$, thus in the case of ultrapowers.

