Two Types of Trilocality of Probability and Correlation Tensors.

In this work, we discuss two types of trilocality of probability tensors (PTs) P = 〚 P (a 1 a 2 a 3) 〛 over an outcome set Ω 3 and correlation tensors (CTs) P = 〚 P (a 1 a 2 a 3 | x 1 x 2 x 3) 〛 over an outcome-input set Δ 3 based on a triangle network and described by continuous (integral) and discrete (sum) trilocal hidden variable models (C-triLHVMs and D-triLHVMs). We say that a PT (or CT) P is C-trilocal (resp. D-trilocal) if it can be described by a C-triLHVM (resp. D-triLHVM). It is proved that a PT (resp. CT) is D-trilocal if and only if it can be realized in a triangle network by three shared separable states and a local POVM (resp. a set of local POVMs) performed at each node; a CT is C-trilocal (resp. D-trilocal) if and only if it can be written as a convex combination of the product deterministic CTs with a C-trilocal (resp. D-trilocal) PT as a coefficient tensor. Some properties of the sets consisting of C-trilocal and D-trilocal PTs (resp. C-trilocal and D-trilocal CTs) are proved, including their path-connectedness and partial star-convexity. [ABSTRACT FROM AUTHOR]