Math Problem Statement

A relation R on a set A is defined to be irreflexive if, and only if, for every x ∈ A, x R x; asymmetric if, and only if, for every x, y ∈ A if x R y then y R x; intransitive if, and only if, for every x, y,

z ∈ A, if x R y and y R z then x R z. Let A = {0, 1, 2, 3}, and define a relation R5 on A as follows. R5 =

(0, 0), (0, 1), (0, 2), (1, 2)

Is R5 irreflexive, asymmetric, intransitive, or none of these? (Select all that apply.)

R5 is irreflexive. R5 is asymmetric. R5 is intransitive. R5 is neither irreflexive, asymmetric, nor intransitive.

Solution

To analyze the relation R5R_5 on the set A={0,1,2,3}A = \{0, 1, 2, 3\}, we will check the definitions of irreflexive, asymmetric, and intransitive.

Given Relation R5R_5

R5={(0,0),(0,1),(0,2),(1,2)}R_5 = \{(0, 0), (0, 1), (0, 2), (1, 2)\}

1. Irreflexive

A relation is irreflexive if no element relates to itself, meaning for every xAx \in A, xRxx R x must be false.

  • For 00: (0,0)R5(0, 0) \in R_5 (not irreflexive)
  • For 11: (1,1)R5(1, 1) \notin R_5
  • For 22: (2,2)R5(2, 2) \notin R_5
  • For 33: (3,3)R5(3, 3) \notin R_5

Since (0,0)R5(0, 0) \in R_5, R5 is not irreflexive.

2. Asymmetric

A relation is asymmetric if whenever xRyx R y, then yRxy R x must be false.

  • Check pairs:
    • (0,1)(0, 1): (1,0)R5(1, 0) \notin R_5 (holds)
    • (0,2)(0, 2): (2,0)R5(2, 0) \notin R_5 (holds)
    • (1,2)(1, 2): (2,1)R5(2, 1) \notin R_5 (holds)
    • (0,0)(0, 0): self-pair (asymmetry applies)

Since all pairs satisfy asymmetry, R5 is asymmetric.

3. Intransitive

A relation is intransitive if whenever xRyx R y and yRzy R z, then xRzx R z must be false.

  • Possible pairs:
    • From (0,1)(0, 1) and (1,2)(1, 2): (0,2)R5(0, 2) \in R_5 (violates intransitivity)

Since (0,1)(0, 1) and (1,2)(1, 2) lead to (0,2)(0, 2) also being in R5R_5, R5 is not intransitive.

Conclusion

  • R5 is not irreflexive.
  • R5 is asymmetric.
  • R5 is not intransitive.

Final Answer: R5 is asymmetric.

Do you want more details or have any questions? Here are some follow-up questions you might consider:

  1. What are other examples of asymmetric relations?
  2. How can we prove a relation is transitive?
  3. Can a relation be both irreflexive and asymmetric?
  4. What are the implications of a relation being intransitive?
  5. How can we represent relations graphically?

Tip: Always check definitions carefully to clarify the properties of a relation.

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Math Problem Analysis

Mathematical Concepts

Set Theory
Relations
Properties of Relations

Formulas

Irreflexive: x R x is false for all x
Asymmetric: if x R y then y R x is false
Intransitive: if x R y and y R z, then x R z is false

Theorems

Properties of relations in set theory

Suitable Grade Level

Grades 10-12