On Detecting Total or Partial Symmetry of Switching Functions

This note presents a method for identifying total or partial symmetry of switching functions based on the application of the principle of residue test by numerical methods. The invariance of a switching function under a single interchange of two variables can be readily detected from the equality of some of the residues of expansion about these two variables. This procedure of detecting invariance is directly applied for the identification of total or partial symmetry of a switching function whose variables of symmetry may be either all unprimed (or all primed), mixed, or of multiform nature.