Некоторые проблемы регулярности $f$-квазиметрик

We get a new proof for validity of $T_4$-axiom of separation for weak symmetric $f$-quasimetric spaces. Using this proof we get $T_4$-property for more general classes of $f$-quasimetric spaces. We construct the symmetric $(q,q)$-quasimetric space $(X,d)$ such that distance function $d(u,v)$ is continuous to each variables but $\lim\limits_{n\to\infty}(\rho(x_0,x_n)+\rho(y_0,y_n))=0\nRightarrow\lim\limits_{n\to \infty}\rho(x_n,y_n)=\rho(x_0,y_0)$.