Correct math notation to show min and max of a list of numbers and sign?

Question

I am working on a paper that uses a calculation from DIN 15018. The calculation is only described in text and not as a math equation. I would like to display as an actual equation if possible.

The text from DIN 15018 (English version) is:

The limiting stress ratio χ = minσ/maxσ or minτ/maxτ etc. is the ratio of the numerically smaller limiting stress (minσ, minτ) to the numerically larger limiting stress (maxσ, maxτ). Depending on the (plus or minus) sign of these limiting stresses the ratio fluctuate from -1 to 0 in the alternating stress range, and from 0 to +1 in the pulsating stress range.

This is implemented in c as

double CalculateChiValuesForStress( vector<double> stress)
{
  unsigned long I = stress.size();

  double min = stress[0];
  double max = stress[0];

  for (int i = 1; i < I; i++)
  {
    min = min<stress[i]?min:stress[i];
    max = max>stress[i]?max:stress[i];
  }

  double absmin = fabs(min)<fabs(max)?fabs(min):fabs(max);
  double absmax = fabs(min)>fabs(max)?fabs(min):fabs(max);

  double chi = absmin / absmax * signOfInteger(min / max);

  return chi;

}

Is there a good way to show this as an equation? What I have started with is