SOLUTION: Relation R on the set of positive integers is defined by the rule that aRb means gcd(a, b) = 2. Is R reflexive? Symmetric? Transitive?

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Question 1030750: Relation R on the set of positive integers is defined by the rule that aRb means gcd(a, b) = 2. Is R reflexive? Symmetric? Transitive?
Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
aRb is NOT reflexive since aRa is not always true, e.g., 3R3 = 3, 10R10 = 10, etc..
aRb is symmetric. If aRb is true then bRa is also true, since gcd(a,b) = 2 = gcd(b,a).
aRb is NOT transitive, since 4R6 is true and 6R140 is also true, but 4R140 = 4.