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Worksheets

Relations and Functions

Total questions: 74

Worksheet time: 37mins

Name
Class
Date
1.

Let A = {1,2,3,4} and B = {3,4,5,6}. Find A × B. Choose the correct complete set of ordered pairs.

a)

{(1,3),(1,4),(1,5),(1,6),(2,3),(2,4),(2,5),(2,6),(3,3),(3,4),(3,5),(3,6),(4,3),(4,4),(4,5),(4,6)}

b)

{(3,1),(3,2),(3,3),(3,4),(4,1),(4,2),(4,3),(4,4),(5,1),(5,2),(5,3),(5,4),(6,1),(6,2),(6,3),(6,4)}

c)

{(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,3),(3,4),(3,5)}

d)

{(1,3),(1,4),(2,3),(2,4),(3,3),(3,4),(4,3),(4,4)}

2.

Let A = {1,2,3,4} and B = {3,4,5,6}. Find B × A. Choose the correct complete set of ordered pairs.

a)

{(1,3),(1,4),(1,5),(1,6),(2,3),(2,4),(2,5),(2,6),(3,3),(3,4),(3,5),(3,6),(4,3),(4,4),(4,5),(4,6)}

b)

{(3,1),(3,2),(3,3),(3,4),(4,1),(4,2),(4,3),(4,4),(5,1),(5,2),(5,3),(5,4),(6,1),(6,2),(6,3),(6,4)}

c)

{(3,1),(3,2),(4,1),(4,2),(5,1),(5,2),(6,1),(6,2)}

d)

{(1,3),(2,3),(3,3),(4,3)}

3.

Let A = {1,2,3,4}, B = {3,4,5,6}, and C = {2,4,6}. Find A × (B ∪ C). Choose the correct complete set of ordered pairs.

a)

{(1,2),(1,3),(1,4),(1,5),(1,6),(2,2),(2,3),(2,4),(2,5),(2,6),(3,2),(3,3),(3,4),(3,5),(3,6),(4,2),(4,3),(4,4),(4,5),(4,6)}

b)

{(1,3),(1,4),(1,5),(1,6),(2,3),(2,4),(2,5),(2,6),(3,3),(3,4),(3,5),(3,6),(4,3),(4,4),(4,5),(4,6)}

c)

{(1,2),(2,2),(3,2),(4,2)}

d)

{(1,2),(1,4),(2,4),(3,4),(4,4)}

4.

Let A = {1,2,3,4}, B = {3,4,5,6}, and C = {2,4,6}. Find (A ∩ B) × C. Choose the correct complete set of ordered pairs.

a)

{(3,2),(3,4),(3,6),(4,2),(4,4),(4,6)}

b)

{(1,2),(1,4),(2,2),(2,4),(2,6)}

c)

{(3,2),(3,4),(4,2),(4,4)}

d)

{(2,2),(2,4),(2,6)}

5.

With A = {1,2,3,4}, B = {3,4,5,6}, and C = {2,4,6}, evaluate (A × B) ∩ (B × C). Choose the correct set.

a)

{(3,4),(3,6),(4,4),(4,6)}

b)

{(1,3),(1,4),(2,3),(2,4)}

c)

{(3,2),(3,4),(4,2),(4,4)}

d)

6.

With A = {1,2,3,4}, B = {3,4,5,6}, and C = {2,4,6}, evaluate (A × B) − (B × C). Choose the correct set.

a)

{(1,3),(1,4),(1,5),(1,6),(2,3),(2,4),(2,5),(2,6),(3,3),(3,5),(4,3),(4,5)}

b)

{(3,4),(3,6),(4,4),(4,6)}

c)

{(1,3),(1,4),(2,3),(2,4),(3,3),(3,4),(4,3),(4,4)}

d)

7.

For any non-empty sets A, B, and C, which of the following product-set identities are valid? Select all that apply.

a)

A × (B ∪ C) = (A × B) ∪ (A × C)

b)

(A ∪ B) × C = (A × C) ∪ (B × C)

c)

A × (B ∩ C) = (A × B) ∩ (A × C)

d)

A × (B ∪ C) = (A × B) ∩ (A × C)

8.

For any non-empty sets A, B, and C, which statements are true? Select all that apply.

a)

(A ∩ B) × C = (A × C) ∩ (B × C)

b)

A × (B − C) = (A × B) − (A × C)

c)

(A ∩ B) × C = (A × B) ∪ (A × C)

d)

A × (B − C) = (A × B) ∪ (A × C)

9.

Suppose A, B, C ⊂ Z × Z with A = {(x,y) | y = 5x − 1}, B = {(x,y) | y = 6x}, and C = {(x,y) | 3x − y = −7}. Find A ∩ B.

a)

{(-1,-6)}

b)

{(4,19)}

c)

d)

Z × Z

10.

Suppose A, B, C ⊂ Z × Z with A = {(x,y) | y = 5x − 1}, B = {(x,y) | y = 6x}, and C = {(x,y) | 3x − y = −7}. Find B ∩ C.

a)

b)

{(-1,-6)}

c)

{(4,19)}

d)

Z × Z

11.

Let the universal set be Z × Z and A, B, C ⊂ Z × Z with A = {(x,y) | y = 5x − 1}, B = {(x,y) | y = 6x}, and C = {(x,y) | 3x − y = −7}. Evaluate A̅ ∪ C̅.

a)

{(4,19)}

b)

c)

Z × Z

d)

{(-1,-6)}

12.

Let the universal set be Z × Z and A, B, C ⊂ Z × Z with A = {(x,y) | y = 5x − 1}, B = {(x,y) | y = 6x}, and C = {(x,y) | 3x − y = −7}. Evaluate B̅ ∪ C̅.

a)

Z × Z

b)

c)

{(4,19)}

d)

{(-1,-6)}

13.

Let A = {1, 2, 3, 4, 6} and R be the relation on A defined by a R b if and only if a is a multiple of b. Choose the correct set of ordered pairs for R.

a)

{(1,1), (2,1), (2,2), (3,1), (3,3), (4,1), (4,2), (4,4), (6,1), (6,2), (6,3), (6,6)}

b)

{(1,1), (2,2), (3,3), (4,4), (6,6)}

c)

{(1,1), (2,1), (3,1), (4,1), (6,1)}

d)

{(1,1), (2,1), (2,2), (3,1), (3,3), (4,1), (4,4), (6,1), (6,3), (6,6)}

14.

Let A and B be finite sets with |B| = 3. If there are 4096 relations from A to B, what is |A|?

a)

3

b)

4

c)

5

d)

6

15.

Let A = {1, 2, 3} and B = {2, 4, 5}. Determine |A × B|.

a)

6

b)

8

c)

9

d)

12

16.

Let A = {1, 2, 3} and B = {2, 4, 5}. Determine the number of relations from A to B.

a)

128

b)

256

c)

512

d)

1024

17.

Let A = {1, 2, 3}. Determine the number of binary relations on A.

a)

64

b)

256

c)

512

d)

729

18.

Let A = {1, 2, 3} and B = {2, 4, 5}. Determine the number of relations from A to B that contain both (1, 2) and (1, 5).

a)

64

b)

96

c)

128

d)

256

19.

Let A = {1, 2, 3} and B = {2, 4, 5}. Determine the number of relations from A to B that contain exactly 5 ordered pairs.

a)

84

b)

120

c)

126

d)

210

20.

Let A = {1, 2, 3}. Determine the number of binary relations on A that contain at least 7 ordered pairs.

a)

36

b)

45

c)

46

d)

55

21.

Let A = {1, 2, 3, 4} and R be the relation on A defined by xRy iff y = 2x. Which set of ordered pairs represents R as a subset of A × A?

a)

{(1, 2), (2, 4)}

b)

{(2, 1), (4, 2)}

c)

{(1, 1), (2, 2), (3, 3), (4, 4)}

d)

{(1, 2), (3, 6)}

22.

Let A = {1, 2, 3, 4} and R be the relation on A defined by xRy iff y = 2x. What are the in-degree and out-degree of vertex 2 in the digraph of R?

a)

in-degree 1, out-degree 1

b)

in-degree 0, out-degree 1

c)

in-degree 1, out-degree 0

d)

in-degree 0, out-degree 0

23.

Let A = {1, 2, 3, 4} and R be the relation on A defined by xRy iff y = 2x. Which adjacency matrix M(R), with rows and columns ordered as 1, 2, 3, 4, is correct?

a)

[ [0,1,0,0], [0,0,0,1], [0,0,0,0], [0,0,0,0] ]

b)

[ [1,0,0,0], [0,1,0,0], [0,0,1,0], [0,0,0,1] ]

c)

[ [0,0,1,0], [0,0,0,0], [0,0,0,1], [0,0,0,0] ]

d)

[ [0,1,0,0], [1,0,0,0], [0,0,0,0], [0,0,1,0] ]

24.

Let A = {1, 2, 3, 4, 6} and R be the relation on A defined by aRb iff a is a multiple of b. Which set of ordered pairs correctly represents R as a subset of A × A?

a)

{(1,1), (2,1), (2,2), (3,1), (3,3), (4,1), (4,2), (4,4), (6,1), (6,2), (6,3), (6,6)}

b)

{(1,1), (1,2), (1,3), (1,4), (1,6)}

c)

{(1,1), (2,2), (3,3), (4,4), (6,6)}

d)

{(2,1), (3,2), (4,3), (6,4)}

25.

For the relation on A = {1, 2, 3, 4, 6} defined by aRb iff a is a multiple of b, what are the in-degree and out-degree of vertex 6 in the digraph of R?

a)

in-degree 4, out-degree 1

b)

in-degree 1, out-degree 4

c)

in-degree 2, out-degree 2

d)

in-degree 3, out-degree 2

26.

For the relation on A = {1, 2, 3, 4, 6} defined by aRb iff a is a multiple of b, which adjacency matrix M(R) with rows/columns ordered 1, 2, 3, 4, 6 is correct?

a)

[ [1,1,0,0,0], [1,1,0,1,0], [1,0,1,0,0], [1,1,0,1,0], [1,1,1,0,1] ]

b)

[ [1,0,0,0,0], [0,1,0,0,0], [0,0,1,0,0], [0,0,0,1,0], [0,0,0,0,1] ]

c)

[ [0,1,0,0,0], [1,0,1,0,0], [0,1,0,1,0], [0,0,1,0,1], [1,0,0,1,0] ]

d)

[ [1,0,1,0,0], [0,1,0,1,0], [1,0,1,0,0], [0,1,0,1,0], [0,0,1,0,1] ]

27.

For A = {a, b, c, d, e, f}, the digraph shown represents a relation on A. Which ordered pair is included in the relation?

a)

(a, a)

b)

(a, c)

c)

(b, e)

d)

(d, f)

28.

For A = {a, b, c, d, e, f}, based on the digraph shown for the relation on A, which entry of the adjacency matrix M(R) (rows/columns ordered a, b, c, d, e, f) is 1?

a)

Row d, column c

b)

Row a, column f

c)

Row f, column e

d)

Row c, column d

29.

Let A = {1, 2, 3, 4} and R be a relation on A defined by (a, b) ∈ R iff a divides b. Which set of ordered pairs represents R as a subset of A × A?

a)

{(1,1), (1,2), (1,3), (1,4), (2,2), (2,4), (3,3), (4,4)}

b)

{(1,2), (2,3), (3,4)}

c)

{(1,1), (2,2), (3,3), (4,4)}

d)

{(2,1), (3,1), (4,1)}

30.

For the relation on A = {1, 2, 3, 4} defined by a divides b, which statement about powers of the relation is correct?

a)

R is transitive on A, so R2=RR^2 = R and R3=RR^3 = R

b)

R is symmetric on A, so R^2 = R2=identityR^2 = identity and R^3 = R3=RR^3 = R

c)

R is antisymmetric on A, so R^2 = empty and R^3 = empty

d)

R is reflexive but not transitive, so

31.

Let A = {1,2,3,4}, B = {w,x,y,z}, and C = {5,6,7}. Relations are defined by R1 from A to B and R2, R3 from B to C as R1 = {(1,x),(2,x),(3,y),(3,z)}, R2 = {(x,6)}, and R3 = {(w,5),(w,6)}. Determine R1 ∘ R2.

a)

{(1,6),(2,6)}

b)

c)

{(1,5),(2,5)}

d)

{(3,7)}

32.

Using A = {1,2,3,4}, B = {w,x,y,z}, C = {5,6,7}, with R1 = {(1,x),(2,x),(3,y),(3,z)} and R3 = {(w,5),(w,6)} defined on B × C, find R1 ∘ R3.

a)

b)

{(1,5),(2,5)}

c)

{(3,6)}

d)

{(1,6),(2,6)}

33.

With A = {1,2,3,4}, B = {w,x,y,z}, C = {5,6,7}, R1 = {(1,x),(2,x),(3,y),(3,z)}, and R2 = {(x,6)}, which matrix equals M(R1 ∘ R2) when rows are ordered 1,2,3,4 and columns are ordered 5,6,7?

a)

Rows 1 and 2 have a 1 in column 6; all other entries are 0

b)

Only row 1 has a 1 in column 5; all other entries are 0

c)

Rows 3 and 4 have a 1 in column 7; all other entries are 0

d)

Every diagonal entry is 1

34.

Based on R1 = {(1,x),(2,x),(3,y),(3,z)} and R2 = {(x,6)} over sets A = {1,2,3,4}, B = {w,x,y,z}, and C = {5,6,7}, does M(R1 ∘ R2) equal the Boolean matrix product M(R1) · M(R2)?

a)

Yes, they are equal

b)

No, M(R1 ∘ R2) has strictly more 1s

c)

No, M(R1 ∘ R2) has strictly fewer 1s

d)

Equality holds only if R3 is used instead of R2

35.

Let A be {1, 2, 3, 4} and R be a relation on A defined by R = {(1,2), (1,3), (2,4), (3,2), (3,3), (3,4)}. Which set equals R composed with R, written R2R^2 ?

a)

{(1,4), (1,2), (1,3), (3,4), (3,2), (3,3)}

b)

{(1,2), (1,3), (2,4), (3,2), (3,3), (3,4)}

c)

{(2,2), (2,3), (3,1), (4,4)}

d)

{(1,1), (2,2), (3,3), (4,4)}

36.

With A = 1,2,3,4{1, 2, 3, 4} and R = (1,2),(1,3),(2,4),(3,2),(3,3),(3,4){(1,2), (1,3), (2,4), (3,2), (3,3), (3,4)} , which set equals R3R^3 (that is, R2R^2 composed with RR )?

a)

{(1,4), (1,2), (1,3), (3,4), (3,2), (3,3)}

b)

{(1,2), (2,3), (3,4), (4,1)}

c)

{(1,1), (2,2), (3,3), (4,4)}

d)

{(2,4), (3,2), (3,3), (4,4)}

37.

For A = {1, 2, 3, 4} and R = {(1,2), (1,3), (2,4), (3,2), (3,3), (3,4)}, which 4×4 adjacency matrix M(R) (rows and columns ordered 1,2,3,4) is correct? Give entries row-wise.

a)

Row1: 0 1 1 0; Row2: 0 0 0 1; Row3: 0 1 1 1; Row4: 0 0 0 0

b)

Row1: 1 0 0 0; Row2: 0 1 0 0; Row3: 0 0 1 0; Row4: 0 0 0 1

c)

Row1: 0 1 0 1; Row2: 1 0 0 0; Row3: 0 1 0 1; Row4: 0 0 1 0

d)

Row1: 0 0 1 1; Row2: 0 0 0 1; Row3: 1 0 1 0; Row4: 0 0 0 0

38.

Which 4×4 adjacency matrix M(R^2) (rows and columns ordered 1,2,3,4) matches the digraph of R^2? Give entries row-wise.

a)

Row1: 0 1 1 1; Row2: 0 0 0 0; Row3: 0 1 1 1; Row4: 0 0 0 0

b)

Row1: 0 1 1 0; Row2: 0 0 0 1; Row3: 0 1 1 1; Row4: 0 0 0 0

c)

Row1: 1 0 0 1; Row2: 0 1 0 0; Row3: 0 0 1 0; Row4: 0 0 0 1

d)

Row1: 0 0 0 0; Row2: 0 0 0 0; Row3: 0 0 0 0; Row4: 0 0 0 0

39.

Select all statements that are correct for Boolean matrix multiplication with M(R) corresponding to the relation R on A = {1, 2, 3, 4}.

a)

[M(R)]2[M(R)]^2 equals M(R2)M(R^2)

b)

[M(R)]3[M(R)]^3 equals M(R3)M(R^3)

c)

[M(R)]2[M(R)]^2 equals M(R)M(R)

d)

[M(R)]3[M(R)]^3 equals M(R2)M(R^2)

40.

Given the digraphs of relations R and S on the set A={a,b,c}A=\{a,b,c\} as described: R has edges {(a,a),(a,b),(a,c),(b,c)}\{(a,a),(a,b),(a,c),(b,c)\} and S has edges {(a,c),(b,a),(b,c),(c,c)}\{(a,c),(b,a),(b,c),(c,c)\} . Which set of ordered pairs is RSR\cup S ?

a)

{(a,a),(a,b),(a,c),(b,c)}\{(a,a),(a,b),(a,c),(b,c)\}

b)

{(a,c),(b,a),(b,c),(c,c)}\{(a,c),(b,a),(b,c),(c,c)\}

c)

{(a,a),(a,b),(a,c),(b,a),(b,c),(c,c)}\{(a,a),(a,b),(a,c),(b,a),(b,c),(c,c)\}

d)

{(a,a),(a,b),(a,c),(b,a),(b,b),(b,c),(c,c)}\{(a,a),(a,b),(a,c),(b,a),(b,b),(b,c),(c,c)\}

41.

Using the same digraphs of R on A={a,b,c}A=\{a,b,c\} with edges {(a,a),(a,b),(a,c),(b,c)}\{(a,a),(a,b),(a,c),(b,c)\} , which set of ordered pairs is the complement R\overline{R} taken over A×AA\times A ?

a)

{(b,a),(b,b),(c,a),(c,b),(c,c)}\{(b,a),(b,b),(c,a),(c,b),(c,c)\}

b)

{(a,a),(b,a),(b,b),(c,a),(c,b)}\{(a,a),(b,a),(b,b),(c,a),(c,b)\}

c)

{(a,b),(a,c),(b,c),(c,c)}\{(a,b),(a,c),(b,c),(c,c)\}

d)

{(a,a),(a,b),(a,c),(b,c),(c,c)}\{(a,a),(a,b),(a,c),(b,c),(c,c)\}

42.

From the digraphs of RR and SS on A={a,b,c}A=\{a,b,c\} where R={(a,a),(a,b),(a,c),(b,c)}R=\{(a,a),(a,b),(a,c),(b,c)\} and S={(a,c),(b,a),(b,c),(c,c)}S=\{(a,c),(b,a),(b,c),(c,c)\} , which set of ordered pairs is RSR\cap S ?

a)

{(a,c),(b,c)}\{(a,c),(b,c)\}

b)

{(a,a),(b,a)}\{(a,a),(b,a)\}

c)

{(a,b),(c,c)}\{(a,b),(c,c)\}

d)

{(a,a),(a,c),(b,c)}\{(a,a),(a,c),(b,c)\}

43.

For relation R={(a,a),(a,b),(a,c),(b,c)}R=\{(a,a),(a,b),(a,c),(b,c)\} on A={a,b,c}A=\{a,b,c\} , which set of ordered pairs is the converse (inverse) relation RcR^{c} ?

a)

{(a,a),(b,a),(c,a),(c,b)}\{(a,a),(b,a),(c,a),(c,b)\}

b)

{(a,b),(a,c),(b,c),(c,a)}\{(a,b),(a,c),(b,c),(c,a)\}

c)

{(a,a),(a,b),(a,c),(b,c)}\{(a,a),(a,b),(a,c),(b,c)\}

d)

{(b,b),(c,c),(a,c),(b,a)}\{(b,b),(c,c),(a,c),(b,a)\}

44.

Let A={1,2,3}A = \{1,2,3\} . For the relation R1={(1,2),(2,1),(1,3),(3,1)}R_1 = \{(1,2),(2,1),(1,3),(3,1)\} on AA , select all properties that hold.

a)

Reflexive

b)

Irreflexive

c)

Symmetric

d)

Transitive

e)

Non-transitive

45.

Let A={1,2,3}A = \{1,2,3\} . For the relation R2={(1,1),(2,2),(3,3),(2,3)}R_2 = \{(1,1),(2,2),(3,3),(2,3)\} on AA , select all properties that hold.

a)

Reflexive

b)

Symmetric

c)

Asymmetric

d)

Transitive

e)

Irreflexive

46.

Let A={1,2,3}A = \{1,2,3\} . For the relation R3={(1,1),(2,2),(3,3)}R_3 = \{(1,1),(2,2),(3,3)\} on AA , select all properties that hold.

a)

Reflexive

b)

Symmetric

c)

Transitive

d)

Equivalence relation

47.

Let A={1,2,3}A = \{1,2,3\} . For the relation R4={(1,1),(2,2),(3,3),(2,3),(3,2)}R_4 = \{(1,1),(2,2),(3,3),(2,3),(3,2)\} on AA , select all properties that hold.

a)

Reflexive

b)

Symmetric

c)

Transitive

d)

Equivalence relation

e)

Irreflexive

48.

Let A={1,2,3}A = \{1,2,3\} . For the relation R5={(1,1),(2,3),(3,3)}R_5 = \{(1,1),(2,3),(3,3)\} on AA , select all properties that hold.

a)

Reflexive

b)

Irreflexive

c)

Asymmetric

d)

Symmetric

e)

Transitive

49.

For the relation R6={(2,3),(3,4),(2,4)}R_6 = \{(2,3),(3,4),(2,4)\} , select all properties that hold.

a)

Transitive

b)

Irreflexive

c)

Symmetric

d)

Not symmetric

50.

Let A={1,2,3}A = \{1,2,3\} . For the relation R7={(1,3),(3,2)}R_7 = \{(1,3),(3,2)\} on AA , select all properties that hold.

a)

Irreflexive

b)

Non-transitive

c)

Not symmetric

d)

Reflexive

e)

Transitive

51.

Let A={1,2,3,4}A = \{1,2,3,4\} . Choose a relation on AA that is reflexive and symmetric but not transitive.

a)

{(1,1),(2,2),(3,3),(4,4),(1,2),(2,1),(2,3),(3,2)}\{(1,1),(2,2),(3,3),(4,4),(1,2),(2,1),(2,3),(3,2)\}

b)

{(1,1),(2,2),(3,3),(4,4),(1,2)}\{(1,1),(2,2),(3,3),(4,4),(1,2)\}

c)

{(1,2),(2,1),(2,2)}\{(1,2),(2,1),(2,2)\}

d)

{(1,1),(2,2),(3,3),(4,4)}\{(1,1),(2,2),(3,3),(4,4)\}

52.

Let A={1,2,3,4}A = \{1,2,3,4\} . Choose a relation on AA that is reflexive and transitive but not symmetric.

a)

{(1,1),(2,2),(3,3),(4,4),(1,2)}\{(1,1),(2,2),(3,3),(4,4),(1,2)\}

b)

{(1,1),(2,2),(3,3),(4,4),(1,2),(2,1)}\{(1,1),(2,2),(3,3),(4,4),(1,2),(2,1)\}

c)

{(1,2),(2,1),(2,2)}\{(1,2),(2,1),(2,2)\}

d)

{(1,1),(2,2),(3,3),(4,4)}\{(1,1),(2,2),(3,3),(4,4)\}

53.

Let A={1,2,3,4}A = \{1,2,3,4\} . Choose a relation on AA that is symmetric and transitive but not reflexive.

a)

\emptyset

b)

{(1,1),(2,2),(3,3),(4,4)}\{(1,1),(2,2),(3,3),(4,4)\}

c)

{(1,2),(2,1)}\{(1,2),(2,1)\}

d)

{(1,1),(2,2),(3,3),(4,4),(1,2),(2,1)}\{(1,1),(2,2),(3,3),(4,4),(1,2),(2,1)\}

54.

Let A={1,2,3,4}A=\{1,2,3,4\} and R={(1,1),(1,2),(2,1),(2,2),(3,3),(3,4),(4,3),(4,4)}R=\{(1,1),(1,2),(2,1),(2,2),(3,3),(3,4),(4,3),(4,4)\} be a relation on AA . Select all properties that RR satisfies.

a)

Reflexive

b)

Symmetric

c)

Transitive

d)

None of these

55.

Let A={1,2,3,4,5,6,7,8,9,10,11,12}A=\{1,2,3,4,5,6,7,8,9,10,11,12\} . Define a relation RR on AA by (x,y)R(x,y)\in R if and only if xyx-y is a multiple of 55 . Select all properties that RR satisfies.

a)

Reflexive

b)

Symmetric

c)

Transitive

d)

None of these

56.

Let A=A1A2A3A=A_1\cup A_2\cup A_3 , where A1={1,2}A_1=\{1,2\} , A2={2,3,4}A_2=\{2,3,4\} and A3={5}A_3=\{5\} . Define a relation RR on AA by xRyxRy if and only if xx and yy are in the same set AiA_i for i{1,2,3}i\in\{1,2,3\} . Select all properties that RR satisfies.

a)

Reflexive

b)

Symmetric

c)

Transitive

d)

None of these

57.

For a fixed integer n>1n>1 , let RR be the relation on the set of all integers Z\mathbb{Z} defined by aRbaRb if and only if ab(modn)a\equiv b \pmod n . Select all properties that RR satisfies.

a)

Reflexive

b)

Symmetric

c)

Transitive

d)

None of these

58.

For the equivalence relation R = {(1,1), (1,2), (2,1), (2,2), (3,4), (4,3), (3,3), (4,4)} defined on the set A={1,2,3,4}A=\{1,2,3,4\} , determine the partition of A induced by R.

a)

{{1,2}, {3,4}}

b)

{{1}, {2,3,4}}

c)

{{1,3}, {2,4}}

d)

{{1,2,3,4}}

59.

Find the partition of A induced by R, given A={1,2,3,4,5,6,7,8,9,10,11,12}A=\{1,2,3,4,5,6,7,8,9,10,11,12\} . The relation R is defined by (x,y)R(x,y)\in R iff xyx-y is a multiple of 55 .

a)

{{1,6,11}, {2,7,12}, {3,8}, {4,9}, {5,10}}

b)

{{1,2,3,4,5}, {6,7,8,9,10,11,12}}

c)

{{1,6}, {11,2,7,12}, {3,8,4,9}, {5,10}}

d)

{{1,2,3}, {4,5,6}, {7,8,9}, {10,11,12}}

60.

Let A={1,2,3,4,5,6,7}A=\{1,2,3,4,5,6,7\} and let R be the equivalence relation on A that induces the partition {{1,2},{3},{4,5,7},{6}}\{\{1,2\},\{3\},\{4,5,7\},\{6\}\} . Identify R from the options below.

a)

R = {(1,1),(2,2),(3,3),(4,4),(5,5),(6,6),(7,7),(1,2),(2,1),(4,5),(5,4),(4,7),(7,4),(5,7),(7,5)}

b)

R = {(1,1),(2,2),(3,3),(4,4),(5,5),(6,6),(7,7),(1,2),(2,1),(3,1),(4,5)}

c)

R = {(1,1),(2,2),(3,3),(4,4),(5,5),(6,6),(7,7),(1,2),(2,1),(4,5),(5,4),(4,7),(7,4)}

d)

R = {(1,1),(2,2),(3,3),(4,4),(5,5),(6,6),(7,7),(1,2),(2,1),(3,2),(4,6),(5,7)}

61.

Let A={1,2,3,4,5}A=\{1,2,3,4,5\} . A relation on A×AA\times A is defined by: (x1,y1)(x_1,y_1) is related to (x2,y2)(x_2,y_2) if and only if x1+y1=x2+y2x_1+y_1=x_2+y_2 . Select all properties that this relation satisfies on A×AA\times A .

a)

Reflexive on A×AA\times A

b)

Symmetric

c)

Transitive

d)

Antisymmetric

62.

Let A={1,2,3,4,5}A=\{1,2,3,4,5\} . The relation on A×AA\times A is: (x1,y1)(x_1,y_1) is related to (x2,y2)(x_2,y_2) iff x1+y1=x2+y2x_1+y_1=x_2+y_2 . Which set is the equivalence class of (1,3)(1,3) ?

a)

{(1,3),(2,2),(3,1)}\{(1,3),(2,2),(3,1)\}

b)

{(2,3),(3,2)}\{(2,3),(3,2)\}

c)

{(1,4),(2,3)}\{(1,4),(2,3)\}

d)

{(1,3)}\{(1,3)\}

63.

Let A={1,2,3,4,5}A=\{1,2,3,4,5\} . The relation on A×AA\times A is: (x1,y1)(x_1,y_1) is related to (x2,y2)(x_2,y_2) iff x1+y1=x2+y2x_1+y_1=x_2+y_2 . Which set is the equivalence class of (2,4)(2,4) ?

a)

{(1,5),(2,4),(3,3),(4,2),(5,1)}\{(1,5),(2,4),(3,3),(4,2),(5,1)\}

b)

{(1,5),(2,4)}\{(1,5),(2,4)\}

c)

{(2,5),(3,4),(4,3),(5,2)}\{(2,5),(3,4),(4,3),(5,2)\}

d)

{(5,5)}\{(5,5)\}

64.

Let A={1,2,3,4,5}A=\{1,2,3,4,5\} . The relation on A×AA\times A is: (x1,y1)(x_1,y_1) is related to (x2,y2)(x_2,y_2) iff x1+y1=x2+y2x_1+y_1=x_2+y_2 . Which set is the equivalence class of (1,1)(1,1) ?

a)

{(1,1)}\{(1,1)\}

b)

{(1,1),(2,0)}\{(1,1),(2,0)\}

c)

{(1,2),(2,1)}\{(1,2),(2,1)\}

d)

{(1,1),(2,2)}\{(1,1),(2,2)\}

65.

Let A={1,2,3,4,5}A=\{1,2,3,4,5\} and a relation on A×AA\times A defined by equality of sums: (x1,y1)(x_1,y_1) is related to (x2,y2)(x_2,y_2) iff x1+y1=x2+y2x_1+y_1=x_2+y_2 . Which description correctly gives the partition of A×AA\times A induced by this relation?

a)

All equivalence classes consisting of ordered pairs with constant sum x+y=kx+y=k for k{2,3,4,5,6,7,8,9,10}k\in\{2,3,4,5,6,7,8,9,10\}

b)

Subsets grouping ordered pairs by equal product xyxy

c)

A single class equal to A×AA\times A

d)

Classes grouping ordered pairs by equal difference xyx-y

66.

Find the number of equivalence relations that can be defined on a finite set A with A|A| == 66 .

a)

200

b)

203

c)

205

d)

210

67.

Let A = {1,2,3,4} and R = {(1,1),(1,2),(2,2),(2,4),(1,3),(3,3),(3,4),(1,4),(4,4)} on A. Based on this relation, select all properties that R satisfies on A.

a)

Reflexive

b)

Symmetric

c)

Antisymmetric

d)

Transitive

68.

For A = {1,2,3,4} with R as in the previous question, choose the description that matches the Hasse diagram of (A,R).

a)

A chain with 1 below 2 below 3 below 4

b)

A diamond: 1 at the bottom, 2 and 3 above 1, and 4 at the top connected to both 2 and 3

c)

A square: 1 and 2 on the left, 3 and 4 on the right, with horizontal edges only

d)

A star centered at 1 connected directly to 2, 3, and 4 only

69.

Let R be the relation on A = {1,2,3,4} defined by xRy iff x divides y. Select all properties that R satisfies on A.

a)

Reflexive

b)

Symmetric

c)

Antisymmetric

d)

Transitive

70.

In the Hasse diagram for the divisibility relation on A = {1,2,3,4}, which pair is not a cover relation (i.e., there is an intermediate element between them)?

a)

1 and 2

b)

1 and 3

c)

2 and 4

d)

1 and 4

71.

Let A = {1,2,3,4,6,8,12} and define R by xRy iff x divides y. Select all properties that R satisfies on A.

a)

Reflexive

b)

Symmetric

c)

Antisymmetric

d)

Transitive

72.

In the Hasse diagram for the divisibility relation on A = {1,2,3,4,6,8,12}, which elements cover 4? Select all that apply.

a)

6

b)

8

c)

12

d)

2

73.

Consider the poset of positive divisors of 36 under divisibility, D36 = {1,2,3,4,6,9,12,18,36}. In its Hasse diagram, which elements cover 6? Select all that apply.

a)

9

b)

12

c)

18

d)

36

74.

In the Hasse diagram of the poset of positive divisors of 36 under divisibility, how many maximal elements are there?

a)

1

b)

2

c)

3

d)

4