On the finite topology of a vector space and the domination problem for families of norms

Abstract

Let $V$ be a real or complex vector space. The finite topology of $V$ consists of all the subsets $U$ for which the intersection $U \cap F$ is closed in $F$ for every finite-dimensional linear subspace of $V$. It is known that if $V$ has countable dimension, then this topology coincides with the greatest vector space topology and with the greatest locally convex vector space topology. Here, we note that in this case the finite topology is simply the union of all the normed space topologies. In connection to this problem, we characterize the vector spaces on which every family of norms with given cardinality is dominated.