Is there a point of 𝜔* that sees all others?

Hindman, Neil

doi:10.1090/S0002-9939-1988-0931732-9

Is there a point of $\omega ^ *$ that sees all others?
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by Neil Hindman

Proc. Amer. Math. Soc. 104 (1988), 1235-1238

DOI: https://doi.org/10.1090/S0002-9939-1988-0931732-9

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Abstract:

If the cardinal $c$ of the continuum is singular and $p$ is an ultrafilter on $\omega$ of character $c$, then there is an ultrafilter $q$ on $\omega$ which is not comparable to $p$ in the Rudin-Keisler order.

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