نظرية المعلومات-المحاضرة الثامنة

A channel is said to be symmetric if the set of output symbols can be partitioned into subsets in such a way that for each subset, the probability transition matrix has the following two properties
- each row is a permutation of each remaining row,
- each column (if there are more than one) is a permutation of each remaining column. In mathematics, the notion of permutation relates to the act of arranging all the members of a set into some sequence or order, or if the set is already ordered, rearranging (reordering) its elements, a process called permuting. These differ from combinations, which are selections of some members of a set where order is disregarded. For example, written as tuples, there are six permutations of the set {1,2,3}, namely: (1,2,3), (1,3,2), (2,1,3), (2,3,1), (3,1,2), and (3,2,1).
A channel is said to be symmetric if the set of output symbols can be partitioned into subsets in such a way that for each subset, the probability transition matrix has the following two properties
- each row is a permutation of each remaining row,
- each column (if there are more than one) is a permutation of each remaining column. In mathematics, the notion of permutation relates to the act of arranging all the members of a set into some sequence or order, or if the set is already ordered, rearranging (reordering) its elements, a process called permuting. These differ from combinations, which are selections of some members of a set where order is disregarded. For example, written as tuples, there are six permutations of the set {1,2,3}, namely: (1,2,3), (1,3,2), (2,1,3), (2,3,1), (3,1,2), and (3,2,1).