I've gotten interested in this question since the recent loophole free bell test performed at Delft University (group of Ronald Hanson). In this test they use entanglement swapping which I hadn't heard about before. After some research I even found out that there is such a thing as delayed choice entanglement swapping. http://www.nature.com/nphys/journal/v8/n6/full/nphys2294.html After reading that article I got a similar epiphany of FTL and back in time communication as the writer, matrixising, of this post https://www.physicsforums.com/threads/entanglement-swapping-and-ftl-communication.731061/ This thread ended into some bad communication. The key point of discussion was how the observers Alice and Bob can determine whether their electrons or photons 1 & 4 are entangled or not. Some people communicated that this was not possible since the measurements of the correlations will be similarly random for entangled and non-entangled particle pairs. My question in this matter is what about bell's inequality? Given a set of pairs of particles, isn't there a difference between their correlations (namely violation of the inequality), based on whether the pairs are entangled or not? Isn't this a method to determine entanglement? And isn't this what the article by Xiao-song Ma shows in Figure 3 (While entangled states can show maximalcorrelations in all three bases (the magnitude of all correlation functions equals 1 ideally), separable states can be maximally correlated (ideal correlation function 1) only in one basis, the others being 0)?