👉 In computer programming, a prevoid (also known as a prefix-free string) is a string that does not contain any characters from another string. For example: ```python s = "abcde" prevoid(s) ``` returns an empty string since no characters are missing from the other string. In mathematics, a prevoid is a type of subset in graph theory, where the vertices of the subgraph are all distinct and the edges between them have been removed.