Hi i need help with the following question
Let X={1,2,3,4} and let A be the set x . Define a relation on A by
(x,y)R(w,z)<=>x+y=w+z
Show that R is an equivalence relation on A and describe (as subsets of A) the equivalence classes of R.
The first bit involving that the statement is a equivalence relation, i manged to do the following however i am not sure if it is correct though.
transitive since (x,y)R(x,y)=x+y=x+y
symmetric since (w,z)R(x,y)=w+z=x+y
transitive since (x,y)R(w,z) and let (w,z)R(u,v) ==> (x,y)R(u,v)=x+y=u+v
However i have no idea on how to do the equivalence class stuff.
thanks
yep sorry thats a mistake i was meant to say reflexive for (x,y)R(x,y)=x+y=x+y
as i don't understand what you mean by what pairs are equivalent to (1,2) ?
as in do you just mean that it is (2,1) since both (1,2) and (2,1) have the same elements hence equivalent ?
i am not sure on how to answer.
what so specific about (1,2) what the other numbers 3 and 4 ?
(1,2) i presume this means 1+2=1+2 if symmetric
not sure on about symmetric and transitive relations though since if present it like (1,2)R(3,4) 1+2 does not equal 3+4
i am just guessing here i am not really sure on how to approach the question though.
ok i am not sure exactly on how to finish the question
but am i correct in saying all these are the combination of relations ?
(1,1) =2
(1,2),(2,1)=3
(1,3),(3,1),(2,2)=4
(1,4),(4,1),(2,3),(3,2)=5
(4,2),(2,4),(3,3)=6
(4,3),(3,4)=7
(4,4)=8
I know that for something to expressed in an equivalence class the notat [] is used. however i am just not sure on how to apply it to my question.