Recent content by tringo

thanks a lot. Can you explain more why x1 and x2 doesn't have an infinite sequence of successive 9's? I am slow :) Thank you for all comments. I learn a lot from them.

If we fix y, for example y=1, then for all x in R, f(x,1) is unique, e.g. f(x,1)=x. Then if y=2, how can we map f(x.2) to a value different from f(x,1)? If f(x,y) exists, then f(x1,x2,x3,...,xn), RxRx...xR->R, exists. And then we can use it to reduce the data?

I do not really understand it, then the 2 input injective function exists? Anybody knows one?

For example, in a plane xOy. each couple (x,y) determine a point in the plane. If injective function f exists. it means it will map each point in this plane to a point in x (or y)axis. I think it is a contradiction.

it seems that there is no two input injective formula, RxR->R because the size of domain is R x R then the size of codomain must be > R x R. But here, the size of codomain is R.

Hello, I am looking for an example of two input injective function, f(x1,x2), R x R ->R. I am very grateful if you can find one. Thanks