DEFINITION 3 80t8 集合 The set u is said to be a universal set U={x|x∈P(x)V~(x∈P(x)) 全集 2/24/202111:37PM Deren Chen Zhejiang univ 11
S e t s 集合 2/24/2021 11:37 PM Deren Chen, Zhejiang Univ. 11 DEFINITION 3. The set U is said to be a universal set : U = {x | xP(x) V (x P(x) )} 全集
DEFINITION 4 80t8 集合 Let s be a set. If there are exactly n distinct elements in S where n is a nonnegative integer, we say that s is a finite set and that n is the cardinality of s The cardinality of S is denoted by IS I 集合的基、势 2/24/202111:37PM Deren Chen Zhejiang univ
S e t s 集合 2/24/2021 11:37 PM Deren Chen, Zhejiang Univ. 12 DEFINITION 4. Let S be a set. If there are exactly n distinct elements in S where n is a nonnegative integer, we say that S is a finite set and that n is the cardinality of S. The cardinality of S is denoted by ∣S∣. 集合的基、势
EXAMPLE7 80t8 集合 Let a be the set of odd positive integers less than 10. Then A=5 2/24/202111:37PM Deren Chen Zhejiang univ 13
S e t s 集合 2/24/2021 11:37 PM Deren Chen, Zhejiang Univ. 13 EXAMPLE 7 Let A be the set of odd positive integers less than 10. Then ︱A︱ = 5
EXAMPLE 8 80t8 集合 Let s be the set of letters in the english lphabet Then S= 26 2/24/202111:37PM Deren Chen Zhejiang univ 14
S e t s 集合 2/24/2021 11:37 PM Deren Chen, Zhejiang Univ. 14 EXAMPLE 8 Let S be the set of letters in the English alphabet. Then ︱S︱= 26
EXAMPLE 9 80t8 集合 Since the null set has no elements it follows that I 6I=0 2/24/202111:37PM Deren Chen Zhejiang univ
S e t s 集合 2/24/2021 11:37 PM Deren Chen, Zhejiang Univ. 15 EXAMPLE 9 Since the null set has no elements, it follows that ︱ ︱ = 0