scholarly journals Jordan Isomorphisms on Nest Subalgebras

2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
Aili Yang

This paper is devoted to the study of Jordan isomorphisms on nest subalgebras of factor von Neumann algebras. It is shown that every Jordan isomorphismϕbetween the two nest subalgebrasalgMβandalgMγis either an isomorphism or an anti-isomorphism.

1993 ◽  
Vol 45 (4) ◽  
pp. 695-708 ◽  
Author(s):  
Matej Brešar ◽  
C. Robert Miers

AbstractA map θ: M —> N where M and N are rings is said to preserve commutativity in both directions if the elements a,b ∊ M commute if and only if θ(a) and θ(b) commute. In this paper we show that if M and N are von Neumann algebras with no central summands of type I1 or I2 and θ is a bijective additive map which preserves commutativity in both directions then θ(x) = cφ(x) +f(x) where c is an invertible element in ZN, the center of N, φ M —> N is a Jordan isomorphism of M onto N, and f is an additive map of M into ZN.


2019 ◽  
Author(s):  
Serban-Valentin Stratila ◽  
Laszlo Zsido

Author(s):  
Ivan Bardet ◽  
Ángela Capel ◽  
Cambyse Rouzé

AbstractIn this paper, we derive a new generalisation of the strong subadditivity of the entropy to the setting of general conditional expectations onto arbitrary finite-dimensional von Neumann algebras. This generalisation, referred to as approximate tensorization of the relative entropy, consists in a lower bound for the sum of relative entropies between a given density and its respective projections onto two intersecting von Neumann algebras in terms of the relative entropy between the same density and its projection onto an algebra in the intersection, up to multiplicative and additive constants. In particular, our inequality reduces to the so-called quasi-factorization of the entropy for commuting algebras, which is a key step in modern proofs of the logarithmic Sobolev inequality for classical lattice spin systems. We also provide estimates on the constants in terms of conditions of clustering of correlations in the setting of quantum lattice spin systems. Along the way, we show the equivalence between conditional expectations arising from Petz recovery maps and those of general Davies semigroups.


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