Explore advanced concepts in quantum field theory through this hour-long conference talk by K. Walker from the University of California. Delve into the intricacies of cgifd idempotent completion, examine the topological symmetries of QFTs, and gain insights into generalized Kramers-Wannier duality. Part of the "Categorical Symmetries in Quantum Field Theory" conference and school organized by NCCR SwissMAP, this presentation offers a deep dive into cutting-edge research in theoretical physics.