Let S be the set of all subsets of first 10 natural numbers. If a relation R is defined on set S such that (A, B)∈ R if    A∩B≠ϕ;where  A,B∈S, then R is

ϕ∩ϕ=ϕ⇒(ϕ,ϕ)∉R∴R is not reflexive Clearly R is symmetric but not transitive      (  if A ={1,2,3}  ,  B={ 3, 4 }  , C = {4,5,6} then     A∩B ={3}  ≠ ∅  and  B ∩C ≠∅   but  A ∩C  =∅ .      so not transitive )