Absence of the interpolation property in the consistent normal modal extensions of the Dummett logic (Q1077401)

This is one in a series of papers by the author on interpolation theorems in non-classical propositional logics. It is proved, by constructing a counterexample, that for any normal modal logic L such that S4.3\(\subseteq L\subseteq S4.3+Grz\), L does not have the weakened interpolation property.