Our group studies fundamental problems in planning: how to build intelligent systems that automatically find a course of action that achieves a desired goal. Planning problems of this kind arise in robotics, logistics, scheduling, and industrial optimization, and the same techniques carry over to the verification of computer systems.

A common theme of our research is exploiting the structure of a problem, both to solve it more efficiently and to understand its solutions. Concrete topics we work on include:

• Explainable AI planning. Rather than returning a single plan, we analyze and characterize the solution space of a task: counting plans, describing what the alternatives have in common, and letting users navigate them interactively.
• Compact state space representations. How can an exponential state space be represented compactly by exploiting the problem structure?
• Planning and machine learning. Combining symbolic planning algorithms with learned components, for efficient grounding and solving.
• Domain-independent heuristics. Novel model-based heuristics for planning as search, including abstractions and systematic relaxation.
• Symbolic methods. Encoding planning into SAT and answer set programming, and leveraging off-the-shelf solvers.
• Theoretical foundations. Computational complexity of solving planning problems defined in different formalisms.

about me

I am Daniel Gnad, lecturer (Akademischer Rat) at the Institute of Computer Science at Heidelberg University, and assistant professor at the Machine Reasoning Lab at Linköping University.

I did my studies in Computer Science at Saarland University. After finishing my MSc. degree, I stayed on as a PhD student in the group of Prof. Jörg Hoffmann. In 2022, I joined the Machine Reasoning Lab at Linköping University as a postdoctoral researcher, where I became assistant professor in 2023. In June 2025 I obtained my docent qualification (Swedish Habilitation) at Linköping University. Since May 2025 I am lecturer in Heidelberg and part-time in Linköping. In October 2025 I obtained my Habilitation in Computer Science at Heidelberg University.