As a similarity function, INITIAL returns True only under the following conditions: (1) Both string are non-empty, (2) one string has exactly one non-blank character, (3) the other string has two or more non-blank characters, and (4) the first character of both strings are the same. This function is case sensitive. If either or both strings are empty or blank, the comparator returns False. Example: "S" compared to "SAM" returns True; "SAM" compared to "SALLY" returns False.