Logics with an existential modality
نویسندگان
چکیده
We consider multi-modal logics interpreted over edge-labelled graphs with a modality 〈#〉, where 〈#〉φ means ‘φ is accessible by an edge with some label’. In a logic with finitely many edge labels, 〈#〉 is definable, but if the set of labels is infinite, it is an independent modality. We axiomatise multi-modal K, deterministic multi-modal K, and PDL with converse and a single nominal, extended with #. The latter gives an axiomatisation of the logic PDLpath introduced in [3].
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