Relation is a subset of Cartesian product .


Let us take an example

Let A = {a, b, c, d}

and B = {Aman, Ankit, Baljinder, Chandu, Eklavya}


We define relation as

R = {(x, y): x is the first letter of y, x ∈ A, y ∈ B}


So, our relation R is

R = {(a, Aman), (a, Ankit), (b, Baljinder), (c, Chandu)}


Representing relations with arrow is called arrow diagram

Relation example.jpg

Now, in our relation

Domain = Set of all first elements in R

Domain = {a, b, c}


Note that

Domain  ≠ A


Range = Set of all second elements in R

Range = {Aman, Ankit, Baljinder, Chandu}


Codomain = 2nd set

Codomain = Q = {Aman, Ankit, Baljinder, Chandu, Darshan}

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Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.