# Solution: 2008-9 Integer-valued function

Let $$\mathbb{R}$$ be the set of real numbers and let $$\mathbb{N}$$ be the set of positive integers. Does there exist a function $$f:\mathbb{R}^3\to \mathbb{N}$$ such that f(x,y,z)=f(y,z,w) implies x=y=z=w?

The best solution was submitted by Yang, Hae Hun  (양해훈), 2008학번. Congratulations!

Here is his Solution of Problem 2008-9.

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