Strictly Positive Fragments of the Provability Logic of Heyting Arithmetic

Ana de Almeida Borges, Joost J. Joosten

We determine the strictly positive fragment ${\mathsf{QPL}}^{+}(\mathsf{HA})$ of the quantified provability logic $\mathsf{QPL}(\mathsf{HA})$ of Heyting Arithmetic. We show that $\math…