👉 In mathematics and logic, a nonvacantly defined symbol is one that has no value or meaning. For example, in set theory, an empty set is not vacantly defined since it does not have any elements. Nonvacant means "not filled with anything" or "empty." In the context of mathematical notation, this could be represented by using a symbol like \(\varnothing\) (underscore) instead of a symbol for "undefined." In programming languages like Python, Java, etc.,