A purely model-theoretic proof of the exponential succinctness gap between CTL+ and CTL

We provide a conceptually simple and elementary proof of the exponential succinctness gap between the two branching time temporal logics CTL^+ and CTL. It only uses CTL's small model property instead of automata- or game-theory and combinatorics as in previous proofs by Wilke and Adler/Immerman.