  Dynamic Epistemic Logic makes it possible to model and reason about
information change in multi-agent systems. Information change is mathematically
modeled through epistemic action Kripke models introduced by Baltag et al.
Also, van Ditmarsch interprets the information change as a relation between
epistemic states and sets of epistemic states and to describe it formally, he
considers a special constructor LB called learning operator. Inspired by this,
it seems natural to us that the basic source of information change in a
multi-agent system should be learning an announcement by some agents together,
privately, concurrently or even wrongly. Hence moving along this path, we
introduce the notion of a learning program and prove that all finite K45 action
models can be described by our learning programs
