x_{1} (quote) is a text/word/sequence wherein the characters/phonemes are taken over alphabet x_{2} (set)

For formal language analysis. In mathematical writing, this relationship is sometimes written as "/"; the set of all x1 (where x2 is specified) is x2* (where "*" is the Kleene star); then x1 is an element/member of x2*, and the letters of x1 are elements/members of x2. While each letter in x1 must be an element of x2, there can be elements of x2 that do not appear in x1.

- zilterle'u
- x
_{1}=l_{2}is a formal character-set/alphabet containing letter(s)/characters/digits/terms x_{2}=l_{1}; x_{2}is a letter in formal alphabet x_{1}and is treated formally (it has no meaning, other than possibly being distinct from other letters in x_{1}) - lu'erma
- x
_{1}(letteral) is a letter that occurs in word x_{2}(text); x2 contains an occurrence of x1 as a digit/term in a sequence