I have set of inequalities in two dimension space which represent relation between $X$ and $Y$. now I want a function whose input is $X$ and output is $Y$. In other words, I want $F$ such that $F(X)=Y$ satisfying given inequalities. for example $ X >= 0, Y>=0, X<=63, Y<=15, X>=4Y, X<=4Y+3$
Now in above case if I input X, function should return Y. Hence, for example, in above case $F(0)=0$ and $F(4)=1$ and so on... You can plot these function on WolframAlpha and see how it gives integer solutions. But I'm looking for a function which maps X to Y.
Is it possible to get such function?