练习(见习题) 1(2)(3)(4) 2(1)(3)(5)(6)(10)
练习(见习题) ⚫ 1(2)(3)(4) ⚫ 2(1)(3) (5) (6) (10)
习题评讲 1(2)21,2.3,4={O,{1},{2},{3},{4},{1,2},{1, 3},{1,4},{2,3},{2,4},3,4},{1,2,3},{1, 2,4},{2,3,4},{1,2,3,4}} 3){1,2,3,4,5,6,7,8,9,10 {4}{1,9},{2,8},{3,7},{4,6},{1,2,7},{1,3, 6},{1,4,5},{2,3,5},{1,2,3,4} 注意:没有{5,5}
习题评讲 1(2) 2 {1, 2, 3, 4}={Ø, {1}, {2}, {3}, {4}, {1, 2} , {1, 3}, {1, 4} , {2, 3}, {2, 4} , {3, 4}, {1, 2, 3} , {1, 2, 4} , {2, 3, 4} , {1, 2, 3, 4}} (3) { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10} {4} {{1, 9}, {2, 8}, {3, 7}, {4, 6}, {1, 2, 7}, {1, 3, 6}, {1, 4, 5}, {2, 3, 5}, {1, 2, 3, 4}} 注意：没有{5，5}
习题评讲(续) 2(1){x|x∈N且1≤x≤100} (3)21,2.3,4={B|Bc{1,2,3,4} (5){x|x>0且xmod2=1}
习题评讲(续) 2(1) {x | x N且1 x 100} (3) 2 {1, 2, 3, 4}={B | B {1, 2, 3, 4}} (5) {x | x > 0且 x mod 2 = 1}
习题评讲(续) 2(6){(x,y)|x,y∈[4,9且x+y=10} 即{(4,6),(6,4)5,5)} (10){B|B≤{1,2,…,10}且∑x=10,x ∈B}
习题评讲(续) 2(6) {(x, y) | x, y [4, 9]且x + y = 10} 即{(4,6),(6,4),(5,5)} (10) {B | B {1, 2, ..., 10}且x = 10，x B}
12关系 ●12.1二元关系 ●122等价关系与等价类 ●123关系的合成
1.2 关系 ⚫ 1.2.1 二元关系 ⚫ 1.2.2 等价关系与等价类 ⚫ 1.2.3 关系的合成