Math Problem Statement

The relation RR in the natural numbers N+={1,2,3,…}N+={1,2,3,…} is defined by ==. So, R⊂N+×N+R⊂N+×N+ and R={⟨x,y⟩:x,y∈N+,x=y}R={⟨x,y⟩:x,y∈N+,x=y}.

Irreflexive:   ∀x : ⟨x,x⟩∉R  ∀x : ⟨x,x⟩∉R

Asymmetric:   ∀x,y : ⟨x,y⟩∈R → ⟨y,x⟩∉R  ∀x,y : ⟨x,y⟩∈R → ⟨y,x⟩∉R

Anti-symmetric:   ∀x,y : (⟨x,y⟩∈R ∧ ⟨y,x⟩∈R) → x=y  ∀x,y : (⟨x,y⟩∈R ∧ ⟨y,x⟩∈R) → x=y

Intransitive:   ∀x,y,z : (⟨x,y⟩∈R ∧ ⟨y,z⟩∈R) → ⟨x,z⟩∉R

Solution

Let's break down the given properties one by one to determine whether the relation RR defined as R={x,y:x,yN+,x=y}R = \{ \langle x, y \rangle : x, y \in \mathbb{N}^+, x = y \} satisfies them.

1. Irreflexive:

  • A relation RR is irreflexive if x:x,xR\forall x : \langle x, x \rangle \notin R.
  • However, by the definition of RR, x,xR\langle x, x \rangle \in R for all xN+x \in \mathbb{N}^+ since the relation only contains pairs where x=yx = y.
  • Conclusion: The relation is not irreflexive because x,xR\langle x, x \rangle \in R for all xx.

2. Asymmetric:

  • A relation RR is asymmetric if x,y:x,yRy,xR\forall x, y : \langle x, y \rangle \in R \rightarrow \langle y, x \rangle \notin R.
  • In the case of RR, we only have pairs where x=yx = y, meaning x,y=y,x\langle x, y \rangle = \langle y, x \rangle, so symmetry is always present when x=yx = y.
  • Conclusion: The relation is not asymmetric because x,yR\langle x, y \rangle \in R implies y,xR\langle y, x \rangle \in R when x=yx = y.

3. Anti-symmetric:

  • A relation RR is anti-symmetric if x,y:(x,yRy,xR)x=y\forall x, y : (\langle x, y \rangle \in R \wedge \langle y, x \rangle \in R) \rightarrow x = y.
  • In RR, the only pairs that exist are x,x\langle x, x \rangle, which trivially satisfies the anti-symmetry condition because if x,yR\langle x, y \rangle \in R and y,xR\langle y, x \rangle \in R, then x=yx = y.
  • Conclusion: The relation is anti-symmetric.

4. Intransitive:

  • A relation RR is intransitive if x,y,z:(x,yRy,zR)x,zR\forall x, y, z : (\langle x, y \rangle \in R \wedge \langle y, z \rangle \in R) \rightarrow \langle x, z \rangle \notin R.
  • Since RR only includes pairs where x=yx = y, this condition doesn't hold because if x,yR\langle x, y \rangle \in R and y,zR\langle y, z \rangle \in R, then x=y=zx = y = z, and thus x,zR\langle x, z \rangle \in R.
  • Conclusion: The relation is not intransitive because the transitivity condition holds.

Final Summary:

  • The relation RR is:
    • Not irreflexive
    • Not asymmetric
    • Anti-symmetric
    • Not intransitive

Would you like more details or clarifications?

Here are 5 related questions to expand on the topic:

  1. What is the difference between asymmetric and anti-symmetric relations?
  2. Can a relation be both reflexive and anti-symmetric?
  3. How do transitive and intransitive relations differ in mathematical terms?
  4. What are examples of irreflexive relations in real-world applications?
  5. Can a relation be symmetric and anti-symmetric at the same time?

Tip: Anti-symmetric relations allow pairs x,y\langle x, y \rangle and y,x\langle y, x \rangle only when x=yx = y, so reflexive relations can still be anti-symmetric.

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Math Problem Analysis

Mathematical Concepts

Set Theory
Relations
Properties of Relations

Formulas

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Theorems

Definition of Irreflexive Relation
Definition of Asymmetric Relation
Definition of Anti-symmetric Relation
Definition of Intransitive Relation

Suitable Grade Level

Undergraduate Mathematics