The two properties of the matrix of fuzzy equivalence relation are proved according to the property of fuzzy equivalence relation .
根据模糊等价关系的性质，推得模糊等价关系矩阵的两个性质。
2
The equivalence between theorem of equal angle of view and reversible property of low pair, applied in synthesis of plane four-bar linkage, is demonstrated to reveal essence of their relation.