# how do you do this relation type question

• Apr 21st 2014, 03:45 AM
sozener1
how do you do this relation type question
Attachment 30720

I don't understand how to do this

I'm having difficulty studying discrete maths we've recently done relations but I don't know how to do this question
• Apr 21st 2014, 04:24 AM
romsek
Re: how do you do this relation type question
do you understand what is meant by

reflexive
symmetric
anti-symmetric
transitive?
• Apr 21st 2014, 06:05 AM
sozener1
Re: how do you do this relation type question
what do the arrows mean do you know??
• Apr 21st 2014, 06:26 AM
romsek
Re: how do you do this relation type question
Quote:

Originally Posted by sozener1
what do the arrows mean do you know??

if your relation is R an arrow going from node x to node y means R(x,y)=TRUE or written another way x R y
• Apr 21st 2014, 06:45 AM
HallsofIvy
Re: how do you do this relation type question
Quote:

Originally Posted by sozener1
what do the arrows mean do you know??

This is your problem and you say you have been studying "relations" so this graphic representation of relations should have been defined in your textbook. Also, there are several different notations used for relations, such as "R(x,y)= true" "x R y" and you did not say what notation you are used nor what definition of "relation" you are using.

The simplest definition of "relation of X with Y" I know is "a set of ordered pairs with the first member from set X and the second in Y".
Then we can represent each member of the relation as the ordered pair (x, y). The graphic representation has an arrow from x to y if and only if the pair (x, y) is in the relation.

So, in terms of ordered pairs, the first relation is {(a, a), (a, b), (a, d), (a, e), (b, a), (b, b), (b, d), (b, e), (c, c), (d, a), (d, b), (d, d), (d, e), (e, a), (e, b), (e, d), (e, e), (f, f), (f, h), (f, i), (g, g), (h, f), (h, h), (h, i), (i, f), (i, h), (i, i)}.