(of a relation) holding between a pair of arguments x and y when and only when it holds between y and x, as … is a sibling of … but not … is a brother of … (关系)对称的
adjective [原级]对称的
Moreover, when A is a nondegenerate, symmetric and copositive plus matrix, the sequence converges to a solution of the problem. 此外,当矩阵为非退化对称双正加阵时,该序列收敛。