In mathematical expressions it is common to use symbols for variables and parameters - greek letters are popular. This makes equations more compact and also international - ρ is understood by French and English phycisists to be density.
Most blocks are never assigned symbols. Instead, MERLIN-Expo will generate a symbol from the name. If names of greek letters appear in the name, such as in “Alpha” and “k_beta”, these will be replaced with actual greek letters. The first underscore will be used as a sub notation and every subsequent underscore will be written as a comma (','). For example: