1. , G (. ). , .
2. . G () = [ s ij ],
3. . G , , , . , G. .
4. . , . , . ( ) ( ). .
5. . (a, b) Î G. G ( ) , δ (a,G) = { b ç b ÎB, (, b)ÎG}. G b ( ) , δ ─1 (b, G) = { a ç a ÎA, (, b)ÎG}. , G . G - F/G.
1. .
= {, , , , , , , }; B = {, , , }; G = {(a, b) ç a ÎA, b ÎB; a - b }.
. : A = {6, 5, 2, 8, 10, 1, 4, 12}, a : B = { z, w, l, o }. .
: G = {(6, l), (5, w), (2, z), (8, l), (10, o), (1, z), (4, w), (12, z)}. .
:
G . 8 , . , G .
:
, , y = f (x), . ( ), ( ).
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.
. . , , - :
- G : F/G = {{ z },{ w },{ l },{o}}.
2. = { a, b, c }; B = {1,2,3,4,5,6,7} : G = {(a,2), (b,3), (a,4), (a,6), (b,6)}. .
:
: :
. .
- F/G = {{2,4,6},{3,6},{Æ}}.
.
1. .
= {., ., ., ., .};
B = { , , -, , , , , , ˳ , }.
G = {(a, b)ç a ÎA, b ÎB, a − b }.
2. A = {0,1,2,3,4} B = {5,6,7,8,9} :
a) G1 = {(1,5), (1,6), (2,6), (3,9), (4,9)};
b) G2 = {(0,6), (1,6), (2,7), (3,7),)4,9)};
c) G3 = {(0,6), (1,7), (2,5), (3,9), (4,8)}.
.
G Í ´ = {(a, b)ç a ÎA, b ÎB, (a, b)ÎG}.
( ), : Dom(G) = . (, b)Î G Î . Î .
( ).
G , B: Im(G) = B. b Î B (, b)Î G, , . b Î B . , .
G ( ), . (a, b) . Î b Î B. , .
G , b Î . (a, b) . Î .
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G ( ), , , . Î b Î . (a, b) , .
G ( ), .
G ( ), , .
1. = { a, b, c, d, e } = {1,2,3} G={(a,2), (b,3), (c,1), (d,2), (e,1)}. ( , , , ) . G ( ).
.
- , 1G = A;
- , 2G = ;
- , ;
- , 1Î 2Î .
- .
2. = { a, b, c, d } = {1,2,3,4} G={(a,1), (b,2), (b,3), (d,4)}. ( , , , ) . G ( ).
.
- , 1G ≠ A ( Î );
- , 2G = ;
- , ( b);
- , b Î .
- , .
3. A = R , B = R+ - , G ={(x, y)ç x ÎR, y ÎR+, y = x 2 }. .
. y = x 2 , :
1. , x ÎR - y = x 2 ³ 0;
2. , y ³0 ;
3. , , x ÎR - y = x 2 ³ 0;
4. , y ÎR+, y > 0 R - x 1 = y, x 2 = − y;
5. , .
G Í ´ = {(a, b)ç a ÎA, b ÎB, (a, b)ÎG}. G─1 Í ´ = {(b, a)ç a ÎA, b ÎB, (a, b)ÎG}. G G─1 . G G─1 , G G─1.
.
, . , .
1. = { a, b, c, d }; B = {1, 2, 3, 4, 5}; G = {(a,2), (b,1), (b,5), (d,3)}. .
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. G─1={(2, a), (1, b), (5, b), (3, d)}.
G , , ( b ) .
G─1 , , ( b ).
2. = { a, b, c,}; B = {1, 2, 3}; G = {(a,1), (,3), (b, 2)}. .
. G─1 = {(1, a), (3, ), (2 ,b) }. .
.
1. :
a) G = {1, a), (1, b), (2, a)}; A = {1, 2}, B = { a, b };
b) G = {1,4), (2,3), (3,2), (4,1)}; A = B = {1, 2, 3, 4};
c) G = {(a 1, b 1), (a 2, b 2), (a 3, b 2)}; A = { a 1, a 2, a 3}, B = { b 1, b 2, b 3}.
, . .
() Y , Y. , Î (, ). ( ) , , .
: f Í X´Y, f: XY. , f Y. , Y .
Y, Î. f ().
Î y ÎY, , (, ) Î f, = f (x) , f Y, f (x) f , .
Y , . , , .
. , f ( 1) = f ( 2) , 1 = 2 1, 2 Î . , 1 ≠ 2 f ( 1) ≠ f ( 2). .
, , . , *ÎY *Î, * = f ( *). , - f.
, .
f: XY, . , . : f ─1 : YX.
f (, ), = f (x). f ─1 (, ), = f ─1 (). , .
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, .
1. , ?
A = { a, b, c }, B = {1, 2, 3}.
a) G1 = { a,1), (b,1), (c,2)}
b) G2 = {(a,1), (b,2), (b,3), (c,2)}
c) G3 = {(a,1), (c,2)}.
. G1 ; G2 , b Y 2 3; G3 , .
2. , ,
.
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a) , 1ÎY b ÎX. , 2ÎY .
b) , . , . .
c) 1 , b. , . , .
d) , .
3. , k: RR, k (x) = 4 x + 3 .
. Y R. , = 1 = 2 , k (a 1) = k (a 2),
4 1 + 3 = 4 2 + 3.
, 4 1 = 4 2 , , 1 = 2. k (x). , .
, . , . = b ÎY. = Î, k (a) = b? : 4 1 + 3 = b. . , . , .
k (x) = 4 x + 3 , , .
4. , k (x) = 4 x + 3.
. , . = k (x), , = k ─1(). = 4 x + 3 . k ─1(). , . , : .
1 3- ( = ).
.
1. = {0, 2, 4, 6}, Y = {1, 3, 5, 7}. Y , Y? , ?
a) {(6, 3), (2, 2), (0, 3), (4, 5)};
b) {(2, 3), (4, 7), (0, 1), (6, 5)};
c) {(2, 4), (4, 5), (6, 3)};
d) {(6, 1), (0, 3), (4, 1), (0, 7), (2, 5)}.
2. Z. , ?
a) f (n) = 2 n + 1;
b)
c)
3. . . , . ( ).
a) f: Z Z, f (x) = x 2 + 1;
b) f: N N, f (x) = 2 x ;
c) f: R R, f (x) = 5 x - 1;
d) f: R R,
e) f: R R, f (x) = 2 x - | x |.
4. f: Y f (x) = 1 + 2/ , , 0, Y 1. , . .