PA: blank/empty digit

If included in a digit string, the string is interpreted as if it were not present/uttered at all; in subscripts/indices, if it is the only thing mentioned, the subscript/index is deleted as the quantity becomes that which would be denoted by all higher/shallower/previous levels of indexing: t_{() }= t, t_{i}= t_{i}. On its own, it means the empty digit; a string of only this digit produces the empty digit string of the given length; once evaluated, any string of only this digit produces the empty number. This word is useful for answering questions or simplifyig notation and otherwise repetitious statements. For example: "li so pi'i papa du li so xo so ju'u dau" ("9*11 = 9?9") may be answered with this word (technically, any string of length at least 1 which consists only of this digit would work). This word, in appropriate contexts, may be a target interpretation of xo'e and/or xo'ei; explicit restriction so that the intended digit cannot equal this one would clarify.