The Branes Behind Generalized Symmetry Operators

The modern approach to $m$-form global symmetries in a $d$-dimensional quantum field theory (QFT) entails specifying dimension $d-m-1$ topological generalized symmetry operators which non-trivially link with $m$-dimensional defect operators. In QFTs engineered via string constructions on non-compact geometry $X$, these defects descend from branes wrapped cycles extend localized source / singularity the boundary $\partial X$. arise magnetic dual This provides systematic way read off various properties of such operators, including their worldvolume theories, and resulting fusion rules. We illustrate general features context 6D superconformal where we use F-theory realization theories Defects 3 are charged under suitable 3-form detect non-invertible rule for also sketch how similar considerations hold related systems.