*Definition [#r559a440]
-A topological space (X,τ) will be called ultra regular, or UR, if disjoints points and closed sets are [[ultraseparated]]; equivalently, if S has a basis consisting of clopen sets.

*Reference [#v9aa1d79]
-Staum, Richard, ''The algebra of bounded continuous functions into a nonarchimedean field''., Pacific J. Math. 50 (1974), 169-185.