Let $X$ be a completely regular Hausdorff space, $E$ a real normed space, and let $C_b(X,E)$ be the space of all bounded continuous $E$-valued functions on $X$. We develop the general duality theory of the space $C_b(X,E)$ endowed with locally solid topologies; in particular with the strict topologies ${\beta }_z(X,E)$ for $z=\sigma ,\tau ,t$. As an application, we consider criteria for relative weak-star compactness in the spaces of vector measures $M_z(X,E^{\text{'}})$ for $z=\sigma ,\tau ,t$. It is shown that if a subset $H$ of $M_z(X,E^{\text{'}})$ is relatively $\sigma (M_z(X,E^{\text{'}}),C_b(X,E))$-compact, then the set $conv\left(S\right(H\left)\right)$ is still relatively $\sigma (M_z(X,E^{\text{'}}),C_b(X,E))$-compact...

For a subspace A of a space X, a linear extender φ:C(A) → C(X) is called an $L_{ch}$-extender (resp. $L_{cch}$-extender) if φ(f)[X] is included in the convex hull (resp. closed convex hull) of f[A] for each f ∈ C(A). Consider the following conditions (i)-(vii) for a closed subset A of a GO-space X: (i) A is a retract of X; (ii) A is a retract of the union of A and all clopen convex components of X; (iii) there is a continuous $L_{ch}$-extender φ:C(A × Y) → C(X × Y), with respect to both the compact-open topology and...