Preorder characterizations of lower separation axioms and their applications to foliations and flows

Tomoo Yokoyama

In this paper, we characterize several lower separation axioms $C_0,C_D$, $C_R$, $C_N$, $\lambda$-space, nested, $S_{YS}$, $S_{YY}$, $S_{YS}$, and $S_{\delta }$ using pre-order. To analyze topo…