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RELATIONS AND FUNCTIONS Class 12, NCERT Chapter 1, Theory Introduction The concept of the term ‘relation’ in mathematics has been drawn from the meaning of the relation in the English language, according to which two objects or quantities are related if there is a recognizable connection or link between the two objects or quantities If (a, b) ∈ R, we say that a is related to b under the relation R and we write as a R b. In general, (a, b) ∈ R, we do not bother whether there is a recognizable connection or link between a and b.  2. Types of Relations  In this section, we would like to study different types of relations. We know that a relation in a set A is a subset of A × A. Thus, the empty set φ and A × A are two extreme relations. For illustration, consider a relation R in the set A = {1, 2, 3, 4} given by R = {(a, b): a – b = 10}. This is the empty set, as no pair (a, b) satisfies the condition a – b = 10. Similarly, R′ = {(a, b) : | a – b | ≥ 0} is the...