.集合 set 非负整数集the set of all non-negative integers自然数集 the set of all natural numbers整数集 the set of all positive integers有理数集 the set of all rational numbers实数集 the set of all real numbers元素 element属于 belong to 不属于 not belong to 有限集 finite set无限集 infinite set空集 empty set包含 inclusion ,include包含于 lie in子集 subset真子集 proper subset补集（余集）complementary set 全集 universe交集 intersection偶数集 the set of all even numbers奇数集 the set of all odd numbers含绝对值的不等式 inequalit
