  We construct a class of extended operators in the cohomology of a pair of
twisted Schur supercharges of 4d N=2 SCFTs. The extended operators are
constructed from the local operators in this cohomology -- the Schur operators
-- by a version of topological descent. They are line, surface, and domain wall
world volume integrals of certain super descendants of Schur operators. Their
world volumes extend in directions transverse to a spatial plane in Minkowski
space-time. As operators in the cohomology of these twisted Schur supercharges,
their correlators are (locally) meromorphic functions only of the positions
where they intersect this plane. This implies the extended operators enlarge
the vertex operator algebra of the Schur operators. We illustrate this enlarged
vertex algebra by computing some extended-operator product expansions within a
subalgebra of it for the free hypermultiplet SCFT.
