document: On the Beth properties of some intuitionistic modal logics Let L be one of the intuitionistic modal logics . As in the classical modal case , we define two different forms of the Beth property for L , which are denoted by B1 and B2 ; in this paper we study the relation among B1 , B2 and the interpolation properties C1 and C2 . It turns out that C1 implies B1 , but contrary to the boolean case , is not equivalent to B1 . It is shown that B2 and C2 are independent , and moreover it comes out that , in contrast to classical case , there exists an extension of the intuitionistic modal logic of S/sub 4 / - type , that has not the property B2 . Finally we give two algebraic properties , that characterize respectively B1 and B2
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