1. ## Discrete Math

Relation as a set of Pairs
Hi,

Can you help in solving this: -

Let X = {1,2,3,4} and R = {(x,y)|x>y}

Write the relation as a set of order pairs. Then find the inverse of relation. Also draw the directed graph of R.

2. Originally Posted by MS BATOOL
Relation as a set of Pairs
Hi,

Can you help in solving this: -

Let X = {1,2,3,4} and R = {(x,y)|x>y}

Write the relation as a set of order pairs. Then find the inverse of relation. Also draw the directed graph of R.
just write out all possible pairs where the first element is greater than the second

so the relation is: R = {(4,3), (4,2), (4,1), (3,2), (3,1), (2,1)}

for the inverse relation, just switch the first and second element in each pair of the original relation

i can't help you with the directed graph, never learnt about that (i would think you just plot the points on the xy-plane and connect them with straight lines, but it might not be that intuitive)

3. Originally Posted by Jhevon
just write out all possible pairs where the first element is greater than the second

so the relation is: R = {(4,3), (4,2), (4,1), (3,2), (3,1), (2,1)}

for the inverse relation, just switch the first and second element in each pair of the original relation

i can't help you with the directed graph, never learnt about that (i would think you just plot the points on the xy-plane and connect them with straight lines, but it might not be that intuitive)
thanks a lot......i was almost near the answer.......but you solve a big problem of mine

4. Originally Posted by MS BATOOL
thanks a lot......i was almost near the answer.......but you solve a big problem of mine
glad to be of assistance. sorry i couldn't help more. i never did much on relations in this setting

5. regarding directed graph, just place 4, 3, 2, 1 elements in differnet locaion and then point them to eachother according to the pairs.. show the arrow on lines as directed from x to y

I hope you understand it now..

6. Originally Posted by cu4mail
regarding directed graph, just place 4, 3, 2, 1 elements in differnet locaion and then point them to eachother according to the pairs.. show the arrow on lines as directed from x to y

I hope you understand it now..
i want to thank you for your care.......i have understood it......thanks again.

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Good Luck.

8. ## Thanks

Originally Posted by mentalcalculation
Yusnier Viera can help you, visit his videos at Yusnier Viera: Video Gallery and you'll see or you can join to his forum at www.yusnierviera.com'forum.aspx
Good Luck.
Dear mentalcalculation, i hope you will be fine....i just want to thanks for your care.....also want to welcome you in mathhelpforum.......thanks again