Fractals and domain theory

We show that a measurement μ on a continuous dcpo D extends to a measurement μ̄ on the convex powerdomain CD iff it is a Lebesgue measurement. In particular, kerμ must be metrizable in its relative Scott topology. Moreover, the space ker μ̄ in its relative Scott topology is homeomorphic to the Vietoris hyperspace of kerμ, i.e., the space of nonempty compact subsets of kerμ in its Vietoris topology – the topology induced by any Hausdorff metric. This enables one to show that Hutchinson’s theorem holds for any finite set of contractions on a domain with a Lebesgue measurement. Finally, after resolving the existence question for Lebesgue measurements on countably based domains, we uncover the following relationship between classical analysis and domain theory: For an ω-continuous dcpo D with max(D) regular, the Vietoris hyperspace of max(D) embeds in max(CD) as the kernel of a measurement on CD.