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equivalence relations
I am having a very hard time understanding how to tell whether relations are
reflexive, symmetric, and transitive.
reflexive x = y
symmetric x = y and y = x
transitive x = y and y = z
I just dont know how to go about working the problems. Here are the problems.
Determine which of the reflexive, symmetric, and transitive properties are satisified by the given relation R defined on se S, and stat whether R is an equivalence relation on S.
S = {1,2,3,4,5,6,7,8} and x R y means that x - y = 0.
S = {1,2,3,4,5,6,7,8} and x R y means that x > y
If someone can help me work thru the first one I can probably figure out the second one.
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For #1.
Reflexive: is it true that x-x=0 for all x? If so, the relation is reflexive.
Symmetric: is it true that if x-y=0 then y-x=0? If so, the relation is Symmetric.
Transitive: is it true that if x-y=0 & y-z=0 then x=z=0? If so the relation is transitive.
Do note that x-y=0 if and only if x=y.
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So would I be safe to assume that #1 is only reflexive?
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And number 2 is reflexive and transitive?
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No. #1 are all three.
And
#2 only transitive.
thus it is reflexsive for all
.
If
then
, thus it is symterric.
If
and
then
, thus it is transitive.
Similary with <
It is not true that,
for all 
It is not true that,
If
then 
It is true that,
and
then 
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Thanks for the explanation.