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Аксиоматические исчисления для интуиционистских аналогов логик контрфактических кондиционалов
The article provides an axiomatization of proper extensions of the basic intuitionistic conditional logic IntCK, first formulated by G.K. Olkhovikov [6]: we define intuitionistic counterparts of D. Lewis’s counterfactual logics [5], J. Burgess’s [1] and J. Pollock’s [7] conditional logics; moreover, several weaker extensions are defined through axiom schemas of conditional reflexivity and a counterfactual variant of the modus ponens rule. These extensions are strongly complete with respect to suitable birelational semantics in the style of K. Segerberg [8]. A distinctive feature of the obtained calculi, compared to systems defined by I. Ciardelli and X. Liu [2], is that the explicit deductive principles governing the behavior of a weak counterfactual operator ◇→, which is not defined in terms of strong operator □→ and intuitionistic negation, are fixed.