The issue that I am dealing with now ends up with the solution of a second order equation. The solutions are the Z positions of a point in 3D. So, basically I have two points with the Z positions of $Z_i (i=1,2)$.
To choose between these two points I need to define the equation $|Z_i-C|$ where $C$ is a constant. The appropriate $Z_i$ is the one that minimizes this equation ($|Z_i-C|$).
Now I am wondering if there is anyway to mathematically represent this procedure in an equation-form. By equation-form I mean something like $Z= min ( ... |Z_i-C| ... $.
Thank you
What you are looking for is called the $\mathrm{arg\;min}$ operator: $$Z = \mathop{\rm arg\;min}_{Z\in\{Z_1,Z_2\}} |Z-C|$$