A variation of the Zamolodchikov-Faddeev algebra over a finite dimensional Hilbert space H and an involutive unitary R-Matrix S is studied. This algebra carries a natural vacuum state, and the corresponding Fock representation spaces F S (H) are shown to satisfyand R (on K ⊗ K). This analysis generalises the well-known structure of Bose/Fermi Fock spaces and a recent result of Pennig.It is also discussed to which extent the Fock representation depends on the underlying R-matrix, and applications to quantum field theory (scaling limits of integrable models) are sketched.

We construct explicit examples of half-sided modular inclusions $$\mathcal {N}\subset \mathcal {M}$$ N ⊂ M of von Neumann algebras with trivial relative commutants. After stating a general criterion for triviality of the relative commutant in terms of an algebra localized at infinity, we consider a second quantization inclusion $$\mathcal {N}\subset \mathcal {M}$$ N ⊂ M with large relative commutant and construct a one-parameter family $$\mathcal {N}_\kappa \subset \mathcal {M}_\kappa $$ N κ ⊂ M κ , $$\kappa \ge 0$$ κ ≥ 0 , of half-sided inclusions such that $$\mathcal {N}_0=\mathcal {N}$$ N 0 = N , $$\mathcal {M}_0=\mathcal {M}$$ M 0 = M and $$\mathcal {N}_\kappa '\cap \mathcal {M}_\kappa =\mathbb {C}1$$ N κ ′ ∩ M κ = C 1 for $$\kappa >0$$ κ > 0 . The technique we use is an explicit deformation procedure (warped convolution), and we explain the relation of this result to the construction of chiral conformal quantum field theories on the real line and on the circle.