EASY
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A relation R on set A={1,2,3,4,5,6} is defined by R={(a,b)R:|a-b|0}. Check whether the relation R is universal relation or not. Explain your answer.

Important Questions on Set Theory and Relations

EASY
Let ρ1 and ρ2 be two equivalence relations defined on a non-void set S. Then
EASY
Consider the non-empty set consisting of children in a family and a relation R defined as aRb if a is brother of b. Then R is
EASY
Let A={1,2,3,4,5} and R be a relation defined by R={(x,y):x,yA,x+y=5}. Then, R is
EASY
Consider the following two binary relations on the set A=a, b, c : R1=c, a, b, b, a, c, c, c, b, c, a, a and R2=a, b, b, a, c, c, c, a, a, a, b, b, a, c, then :
MEDIUM
Let ρ be a relation defined on N, the set of natural numbers, as ρ={(x,y)N×N:2x+y=41}. Then
EASY
If A=1,2,3,4 then which one of the following is reflexive?
HARD
Let Z denote the set of all integers. If a relation R is defined on Z as follows:
( x, y) R if and only if x is multiple of y, then R is
HARD
Let R1 and R2 be two relations defined as follows :

R1=a, bR2:a2+b2Q and R2=a, bR2:a2+b2Q, where Q is the set of all rational numbers, then

MEDIUM
A set P={7, 21, 28, 42, 14, 0} is given. A relation R holds on elements a and b of set P if either a is a factor of b or b is a factor of a. The relation R on the set P is
MEDIUM
The relation R defined in the set 1,2,3,4,5,6 as R=a,b:b=a+1 is
MEDIUM
Let R be a relation on the set of all natural numbers given by a R ba divides b2.

Which of the following properties does R satisfy?

I. Reflexivity II. Symmetry III. Transitivity
MEDIUM
On R, a relation ρ is defined by xρy if and only if x-y is zero or irrational. Then,
MEDIUM
Let R be the real line. Consider the following subsets of the plane R×R

S={x, y:y=x+1 and 0<x<2}

T={x, y:x-y is an integer}

Which of the following is true?
EASY

Let R be the real line. Consider the following subsets of the plane R×R

S={(x,y)y=x+1,0<x<2}

T={(x,y)x-y is an integer }. Which one of the following is true?

EASY
Let P be the relation defined on the set of all real numbers such that P=a,b:sec2a-tan2b=1. Then, P is
MEDIUM
Let the relation $\rho$ be defined on R as aρb if 1+ab>0. Then
MEDIUM
If a relation R on  the set 1,2,3 be defined by R=1,1, then R is
EASY
In the set  of natural numbers, the relation R=x,y:x>y+5 is
MEDIUM
Let the relation ρ be defined on R by aρb holds if and only if a-b is zero or irrational, then
MEDIUM
On the set R of real numbers, the relation ρ is defined by xρy,(x,y)R