2QBF: Challenges and Solutions

2QBF is a special form \(\forall \varvec{x} \exists \varvec{y}.\phi \) of the quantified Boolean formula (QBF) restricted to only two quantification layers, where \(\phi \) is a quantifier-free formula. Despite its restricted form, it provides a framework for a wide range of applications, such as artificial intelligence, graph theory, synthesis, etc. In this work, we overview two main 2QBF challenges in terms of solving and certification. We contribute several improvements to existing solving approaches and study how the corresponding approaches affect certification. We further conduct an extensive experimental comparison on both competition and application benchmarks to demonstrate strengths of the proposed methodology.