
Topic review (newest first)
 anonimnystefy
 20130703 23:25:09
No problem. Of, course, the standard relartion notation is to use the name of the relation, e.g.:
To note that 1 is related to 3 with respect to the relation R, you'd say 1R3. It's like if you said 1<3.
 bob bundy
 20130703 06:40:44
Thanks. I'm happy now.
Bob
 anonimnystefy
 20130703 06:39:15
 bob bundy
 20130703 06:38:18
OK. Thanks. I'm going to use > to mean 'is related to'
So
1 > 1 2 > 2 1 > 3
looks to me like another way to describe the relation.
Then to test for transitivity I must check out all the three way combinations:
1 > 1 >1 Is it true that element 1 > element 3 ? Yes, because 1 > 1 1 > 1 >3 Is it true that element 1 > element 3 ? Yes, because 1 > 3 2 > 2 >2 Is it true that element 1 > element 3 ? Yes, because 2 > 2 1 > 3 >? 3 > is undefined.
There are no more triples so I have, by exhaustion, tested and proved transitivity for this relation.
How does that sound?
Bob
 anonimnystefy
 20130703 06:23:58
What you are thinking of is an operation.
A relation is something like =,<=,>=,...
For example, on the set {1,2,3} you can define = as {(1,1),(2,2),(3,3)], i.e., the set of ordered pairs for which the relation holds.
Also, > : {(2,1),(3,1),(3,2)} < : {(1,2),(1,3),(2,3)}
 bob bundy
 20130703 06:20:46
Sorry. maybe I'm just thick; but how is that a relation? It just looks like a set of ordered pairs.
This is what I think of when I've got a relation:
eg. A = (1,2,3} B = (1,4,9} A is related to be by (element in A)^2 = (corresponding element in B)
Please spell it out for me.
Bob
 anonimnystefy
 20130703 06:10:52
No, the relation R is {{1,1},{2,2},{1,3}}, like it says.
 bob bundy
 20130703 05:55:19
???
Is R the relation
1 > 1 2 > 2 1 > 3
because that doesn't look right to me.
Bob
 anonimnystefy
 20130703 05:35:07
 mukesh
 20130703 05:08:08
sir,if A is a set such tht A=$1,2,3$ and R=[(1,1),(2,2),(1,3)] is it transitive relation?plse explain,
