Perhaps I can better formulate my problem.
I have three real numbers A, C, D with C < A.
How can I write an algebraic function that gives the median number,
The min(max(C,D),A) works but I must get rid of the nested function.
And also, I cannot use absolute values.
Note that, being C < A, there are only three cases to consider:
1) D < C < A (mid = C)
2) C < D < A (mid = D)
3) C < A < D (mid = A)
Therefore, the mid numer is one of these two: max(D,C) or min(A,D).
But don't see how to progress and come out with the right one.