Well the problem is that it’s easy to run out of letters with only the latin alphabet. Also some fields do have conventions. For instance in numerical linear a

Well the problem is that it’s easy to run out of letters with only the latin alphabet. Also some fields do have conventions. For instance in numerical linear algebra, many papers us the rules of (1) matrix in roman capital letters (2) vectors in roman normal-size letters (3) scalars in greek normal-size letters.