How many symmetric relations

For a reflexive relation , we have ordered pairs of the form a, a which are also symmetric. We have 2 n such ordered pairs. Hence, the number of symmetric relations is 2 n. Check if R is a symmetric relation. Determine the elements which should be in R to make R a symmetric relation. The null or empty set is a symmetric relation for every set. Since there are no elements in an empty set , the conditions for symmetric relation hold true.

It is possible for a set to be symmetric and antisymmetric but not always. Learn Practice Download. Symmetric Relations In discrete mathematics, a symmetric relation between two or more elements of a set is such that if the first element is related to the second element, then the second element is also related to the first element as defined by the relation. What are Symmetric Relations?

Asymmetric, Anti-symmetric and Symmetric Relations 3. Count number of triplets with product equal to given number with duplicates allowed Set Permutation of a number whose sum with the original number is equal to another given number. Minimum number of moves to make M and N equal by repeatedly adding any divisor of number to itself except 1 and the number. Print all numbers whose set of prime factors is a subset of the set of the prime factors of X. Article Contributed By :.

Easy Normal Medium Hard Expert. Writing code in comment? Please use ide. Load Comments. What's New. Most popular in Combinatorial. Ask Question. Asked 10 years, 10 months ago. Active 30 days ago. Viewed 47k times. Thank you. Anonymous Anonymous 3 3 gold badges 5 5 silver badges 6 6 bronze badges. Since I don't just want to give the answer, here's a good hint: how many total relations are there for an n-element set, and what do they correspond to?

Now, what do the symmetric relations correspond to, and can you use that to find your answer? In the past people have been flamed for asking what Steven is asking above. Do we have a new policy on, now that the elections are over? From here, I don't see how to find the number of all the symmetric relations - I just know that it has to be symmetric from the diagonal or on the diagonal. Show 5 more comments. Active Oldest Votes. Add a comment. Shiv Gupta Shiv Gupta 1 1 silver badge 3 3 bronze badges.

Start with 1 bit, you can have 2 numbers 0 and 1. For 2 bits you can have 4 namely, 00, 01, 10, and