Negation | Condition | In general, things that are in the text are assumed to exist by the very nature of them being discussed. Sometimes, however, they do not: the text says that they are negative, or absent. In other cases, the text may say that something is unknown or uncertain. Negation signals cater for this, and are used to mark the part of the text that shows absence, negation and uncertainty. Negation signals may have values of absent and uncertain. | In example 4, the text "no evidence" signals the absence of the secondaries (more precisely, the absence of any finding of secondaries). |