I read an article, I saw a sentence that I did not understand because I do not know the topology of Mackey. This sentence is:
"We shall denote by $\tau$ the Mackey topology on the dual space $X^*$. Since $X$ is supposed separable, the unit ball of $X^*$ has a countable, $\tau$-dense subset $D$ with $D = -D$; also, the set $H$ spanned by all rational linear combinations of vectors in $D$ is $\tau$-dense in $X^*$"
Please, can I find someone who already knows this topology and can send me a book or article on the above result.