You can also use the and keys
Deletions are marked like this Additions are marked like this

In mathematics and computer science, a bifix-free word (or "unbordered" or "primary" word) is a word that has no strict prefix that is also a suffix.

For example, "abaabb" is a bifix-free word because the only prefix ending in "bb" is the entire word. On the other hand, the word "abaab" is not bifix-free because "ab" is both a prefix and suffix.

In mathematics and computer science, a bifix-free word (or "unbordered" or "primary" word) is a word that has no strict prefix that is also a suffix.

For example, "abaabb" is a bifix-free word because the only prefix ending in "bb" is the entire word. On the other hand, the word "abaab" is not bifix-free because "ab" is both a prefix and suffix.

The phrase "bifix-free" comes from the word "bifix," which refers to a substring that is both a prefix and suffix.