<i>S</i>(<i>α</i>) spaces and regular Hausdorff extensions
<i>S</i>(<i>α</i>) spaces and regular Hausdorff extensions
A class of separation axiomsSi a), one for each ordinal a > 0, is introduced.Axiom S(l) is the Hausdorff property, S(2) is Urysohn and regular implies S(w o ) 9 where w 0 is the first infinite ordinal.Minimal S(a) and S(α)-closed spaces are characterized, and many of the known results …