In this third of three worksheets I demonstrate some Maple procedures which implement much of the null electrovacuum computations of "The spacetime geometry of a null electromagnetic field", by C. G. Torre. See the preceding worksheets (I and II) for additional details and illustrations. I have provided a Maple worksheet and a PDF version of that worksheet.
Torre, Charles G., "Rainich-type Conditions For Null Electrovacuum Spacetimes III" (2014). Research Vignettes. Paper 7.