Strong Versions of Normality
Scott W. Williams, Haoxuan Zhou · 2020
A space X is called monotonically normal (or MN for brevity) provided that for each pair (H,K) of disjoint closed sets, there is an open set m(H.K) satisfying two conditions: MN 1 . Hcm(H,K)çcl(m(H,K))çX/K. MN 2 . If HçKi and K C Ki, then m(H.K) ç m(Hi,Ki).