Hi, For variable names, the documentation states - "The Wolfram Language uses both uppercase and lowercase letters. There is a convention that built?in Wolfram Language objects always have names starting with uppercase (capital) letters. To avoid confusion, you should always choose names for your own variables that start with lowercase letters." I have some groups of formulas that use both upper and lower case letters - the capital letter means one thing and the same lowercase letter means something different yet related to the capital letter. Can I use capital letters with subscripts or superscripts for variable names? Or, does that violate the above documentation guidance? Thanks, Mike