2 problems

Let $\mathsf{MSO}^\phi(\sharp)$ be monadic second-order logic with the Härtig quantifier, and call an arithmetical predicate directly definable when it is defined by the logic in t…

Let $NDL$ be the generalized dynamic logic discussed in the paper, and let Henkin-style second-order logic (HSOL) be the corresponding Henkin semantics for second-order logic. A pr…