Vertex Algebras for S-duality

We define new deformable families of vertex operator algebras A[g,Ψ,σ]$$\mathfrak {A}[\mathfrak {g}, \Psi , \sigma ]$$ associated to a large set of S-duality operations in four-dimensional supersymmetric gauge theory. They are defined as algebras of protected operators for two-dimensional supersymmetric junctions which interpolate between a Dirichlet boundary condition and its S-duality image. The A[g,Ψ,σ]$$\mathfrak {A}[\mathfrak {g}, \Psi , …