Twisted intertwining operators and tensor products of (generalized)
twisted modules
Twisted intertwining operators and tensor products of (generalized)
twisted modules
We study the general twisted intertwining operators (intertwining operators among twisted modules) for a vertex operator algebra $V$. We give the skew-symmetry and contragredient isomorphisms between spaces of twisted intertwining operators and also prove some other properties of twisted intertwining operators. Using twisted intertwining operators, we introduce a notion of …