Action frames for weak relevant logics
Abstract
The article introduces extended models for the propositional dynamic
logic PDL. In extended models, valuation assigns to every state a
set of atomic formulas and a PDL program. The program is informally
construed as an action preferred by a contextually fixed agent. PDL is then extended by introducing a conditional connective expressing partial correctness claims. The main contribution of the article is the observation that the partial correctness conditional is in fact a substructural implication. It is shown that a variant of the minimal distributive substructural logic DB is a fragment of PDLS, an extension of PDL that contains the partial correctness conditional and fusion. It is also shown that the main results can be extended to a specific class of positive substructural logics.