If so, which one is the dependent and which one is independent?
If x+y= 1 => x = 1- y, x, y belongs to R, then y is independent and x is dependent. But in case of x > y, how we have to define the dependency between the two variables.
I am not sure I understand. If X and Y are random variables then you could have X a uniform random variable on [0,1] and Y an independent random variable uniformly distributed on [3, 5]. Then Y>X but Y and X remain independent.
Actually in my case there are two mappings in two separate metric spaces, for data taken by the random variable X forms a mapping and Y also forms a mapping on two different metric spaces. We can not consider these two variables X and Y as we used in regression analysis.