[Maths Class Notes] on Asymmetric Relation Pdf for Exam

In discrete mathematics, the opposite of symmetric relation is asymmetric relation. In a set X, if one element is less than another element, agrees with the one relation, then the other element will not be less than the first one. Therefore, less than (>), greater than (<), and minus (-) are examples of asymmetric relations. 

We can even say that the ordered pair of set X agrees with the condition of asymmetric only if the reverse of the ordered pair does not agree with the condition. This makes it identical from symmetric relation, where even the exact opposite of their orders are reversed, the condition is satisfied. There are 8 types of relations, these are :

• Empty Relation

• Universal Relation

• Identity Relation

• Inverse Relation

• Reflexive Relation

• Symmetric Relation

• Transitive Relation

• Equivalence Relation

 

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Domain and Range

If there are two relations A and B and the relation for A and B is R (a,b), then the domain is stated as the set { a | (a,b) ∈ R for some b in B} and range is stated as the set {b | (a,b) ∈ R for some an in A}.

 

Asymmetric Relation Definition

Asymmetric relation is the opposite of symmetric relation but not considered as equivalent to antisymmetric relation.

 

In Set theory, A relation R on a set A is known as asymmetric relation if no (b,a) ∈ R when (a,b) ∈ R or we can even say that relation R on set A is symmetric if only if (a,b) ∈ R⟹(b, a) ∉R.

 

For example: If R is a relation on set A= (18,9) then (9,18) ∈ R indicates 18>9 but (9,18) R,  Since 9 is not greater than 18. 

 

Note- Asymmetric relation is the opposite of symmetric relation but not considered as equivalent to antisymmetric relation.

 

The mathematical operators -,< and > are asymmetric examples whereas  =, ≥, ≤, are considered as the twins of ()  and do not agree with the asymmetric condition. 

 

Asymmetrical Relation Properties

Some basic asymmetrical relation properties  are :

• A relation is considered as asymmetric if it is both antisymmetric and irreflexive or else it is not.

• Limitations and opposite of asymmetric relations are considered as asymmetric relations. For example- the inverse of less than is also an asymmetric relation.

• Every asymmetric relation is not strictly in the partial order.

• Subsequently, if a relation is of a strict partial order, then it will be considered as transitive and symmetric.

• An asymmetric relation should not have the convex property. For example, the strict subset relation is regarded as asymmetric and neither of the assets such as  {3,4} and  {5,6} is a strict subset of others.

• A transitive relation is considered asymmetric if it is irreflexive or else it is not. For example: if aRb and bRa, transitivity gives aRa contradicting ir-reflexivity.

 

Asymmetric Relation Solved Examples

1. If X= (3,4) and Relation R on set  X is (3,4), then Prove that the Relation is Asymmetric.

 

Solution: Give X= {3,4} and {3,4}∈ R

 

Clearly, we can see that 3 is less than 4 but 4 is not less than 3, hence

{3,4} ∈ R  ⇒ {4,3}∉ R

 

Hence, it is proved that the relation on set X is symmetric

 

Conclusion

This is all about the definition and explanation of asymmetric relation and its different forms. Focus on how the concept has been explained. Understand the concept well so that you can answer questions judiciously.