Quote:
Originally Posted by spearfish Hey all,
I am getting stuck proving the following relation:
x, y are elements of Q^+. x~y iff x = y(2^n) for some integer n.
Here's what I have so far:
Reflexive:
Let x be an element in Q^+.
x = x(2^n).
x/x = 2^n
1 = 2^n
1 = 2^0
1 = 1, Ok so does this prove xRx or do I need further work? Symmetric:
Let x,y be elements in Q+.
Suppose xRy.
x = y(2^n)
Now suppose yRx.
y = x(2^m)
Plugging in for y and solving for x, I get
x = (x(2^n))(2^m)
x = x(2^n+m)
x/x = 2^(n+m), This is what I don't know what to do. What exactly does this result tell me? Do I need further work, or is this completely the wrong approach? Please somebody.
Transitive:
Let x,y,z be elements in Q+
Suppose xRy.
x = y(2^n)
Suppose yRz.
y = z(2^m).
Pluggin in and solving.
x = (z(2^m))(2^n)
x = z(2^m+n), Once again, now what?
Please explain my faults and show how to correct. Explanations would be very helpful. Thanks |
Actually what you have done to prove reflexive and transient property of R is correct ,
But you have made a mistake on the proof of symmetric property of R .
You have taken that if (x,y) belongs to R x = y (2^n) , y = x (2^m)
Mistake is there
if (x,y) belongs to R x = y (2^n) ,
y = x (2^-n) we know that -n is also an Integer
therefore R is symmetric .